If finding friendship with one other person is hard, try finding friendship between two couples. What does is take? Each member of both couples must find at least one friend among the other couple in such a way that all members are included. If any one person is left out of friendship, the couples are not entirely friends.
In the best case scenario, all four people are friends with all other three. This is rare, but happens. However, even this arrangement is fragile. A shift in the life circumstances of any of the four people can upset the balance and change the character of the friendship. The probability of such a shift happening in any given year is substantially higher than that of a shift happening among a single couple (a relatively high probability to begin with.
For instance, if a single individual has a 20% chance of a major shift in circumstances in a given year, then a couple has a 36% chance that one or more will experience a shift, and a set of two couples -- 59%. This is just to illustrate why close friendships between two couples are less stable than between two people.
What intertype relations might be more favorable for such a friendship? Among any four people, there is a dizzying variety of possible combinations of intertype relations. And yet, some tend to be more common than others.
It's easiest to recognize friendships between two dual couples. In my experience, it seems relatively common to have:
- dual couples
- activator couples
- semi-duality couples
- extinguishment couples
(where the relationship is defined by the intertype relation between any two individuals of the same sex)
A relationship between two couples may become unstable if there is cause for attraction between any two members of the opposite sex. Therefore, identity relations between couples are rarer than duality, and mirror rarer than activator. Identity friends typically have to keep their spouses out of the friendship to avoid sparking jealousy and concealed sexual competition between the two males or two females.
Since I have a lot of activator friends, I frequently encounter the "activator couple" scenario. Do couple friendships form in all cases? Only in about a third at most. It seems that most such friendships are saboteuged by rejection between "mirrors." In other words, an IEE and LSE may be close friends and may want to include the spouses in the friendship, but either the SLI spouse rejects the LSE or the EII spouse rejects the IEE.
There seems to be no surefire way of predicting rejection. It seems particularly common for the dual spouse to perceive the activator friend as a competitor for influence on the spouse. The more time the two spend together, the less time the dual gets with his or her spouse.
So, you can see how difficult it is for even an activator couple friendship to materialize. The likelihood of rejection between two opposite sex "mirrors" is quite high.
Paradoxically, more socionically distant relations between couples may be "safer" in the sense that the same sex friend of your spouse is less likely to be perceived as a direct competitor to you. However, such relationships will also likely not develop the same degree of closeness and trust.
As soon as we introduce non-dual couples, things get more complex since the likelihood of imbalance between the intertype relations of one member of a couple and the other member rises.
For instance, a LIE-ILI (mirror) couple (male member listed first for consistency) may become friends with a ESI-LIE couple (dual). In this scenario, two people get a dual relation out of the friendship, one gets an activation relation, and one gets "just" a mirror relation. It's easy to see that here the relationship will hinge mostly upon the ESI, who is "needed" by everyone else. Probably, the other three will only be able to talk amongst themselves, but when the ESI comes around, varied activities will become both possible and fun. It's typically hard to have extended fun with identity partners, mirror partners, kindred partners, etc.
The ideal friends for a LIE-ILI couple might be a ESI-SEE couple, but what are the odds of finding one? Likewise, the ideal friends for a LSI-SEE couple might be an EIE-ILI couple, but I would the odds of two such couples finding each other would be very low indeed.
Generally, it seems that the less socionically favorable the intertype relation between a couple, the more difficult it is to maintain friendships with other couples.
To avoid sociono-centricism, it should be noted that the less favorable AND stable a couple's relationship is in general (not just in socionic terms), the greater difficulty they will have maintaining friendships with other couples. This applies to duals with an instable relationship just as much as to non-duals with a stable relationship. Can duals have an instable relationship? Of course. (Nonetheless, dual relations appear to be more common than others.)
Furthermore, in practice friendship is based not so much on socionics ("we just feel good around each other -- that's why we're friends") as upon shared interests and history ("we enjoy doing X together, we've been through a lot together, we have a lot to talk about"). Socionic factors certainly influence the likelihood that two people will become and remain friends, but it is far from a 100% determiner.
Looking at interests may help to explain the frequent "mirror rejection" pattern mentioned above. When two activators become friends, they most certainly share some interests and commonalities in values. These shared interests and values won't extend to all areas of life, but they're definitely enough to justify spending time together doing something of mutual interest and talking about life. However, what you share in common with an activator may not be what they share in common with their dual.
For instance, I am passionate about backpacking and the outdoors. A lot of my activator LSE friends have also somewhat enjoyed backpacking -- enough to make trips together generally worthwhile and fun. But what is the probability that someone who enjoys backpacking somewhat, but not passionately like I do, will choose a spouse that also enjoys it? Probably under 50% (the more passionate one is about something, the higher the likelihood they will choose a spouse that shares or sympathizes with the interest). And there you have one possible reason for rejection. The friend's spouse doesn't enjoy or understand backpacking, and is mistrustful of people who make it a central part of their life. Probably, if we were to dig deeper, we would find some other fundamental value differences underlying an interest or disinterest in backpacking that would make itself felt in other ways.
Each thing that just one of the friends is particularly passionate about is similarly prone to cause rejection or mistrust on the part of the other friend's spouse, who, more likely than not, does not sympathize much with the passion.
What seems to increase the likelihood of a compatible intercouple relationship is when both activation partners are equally passionate about their key shared interest/s. This means that it is likely that both have chosen spouses who are at least accepting of and somewhat interested in the area of passion. In this case, everyone can participate and experience enjoyment both from the activity and from the conversations that inevitably result.
But "equally passionate" is just another way of saying that the activator friends are more compatible than two friends who are unequally passionate about their shared interests. Many parameters of compatibility are not encompassed by socionics. Higher compatibility between friends increases the likelihood of compatibility between their spouses and between both couples. If you and your friend have built a friendship upon mediocre compatibility, it is less likely that your spouses can be included successfully in the relationship.
Leaving socionics behind for a moment, friendships between couples are more likely to form on the basis of a common interest or interests among all four members. Socionics becomes one of the limiting factors to the relationship and will tend to make itself felt during longer interaction sessions involving a greater variety of activities (for instance, not just talking about or doing the common interest/hobby, but also eating together, planning logistics, relaxing afterwards, etc.).
Even among two highly compatible couples (say, a complete quadra) differences will arise where one or two people dissent from the majority approach. Dissention can occur on the basis of irrationality-rationality ("I don't like how they don't warn us about what they're going to do"), on the basis of gender ("I'm tired of everything having to be so goal-oriented; why don't you and I take a walk around town together while the men do their thing?"), on the basis of sensitivity ("I just want to be alone for a while"), or any number of other things.
To sum things up, friendship between couples is more difficult and complex than dynamics between two people. Intertype relations between the two couples play a significant role in choice of intercouple friends, but there are a number of other important factors determining the possibility of friendship.