The problems with open relationships are or should be well-known: women are the guardians of sex and men the guardians of commitment, for women it is extremely easy to have sex and men much more difficult, women implicitly trade sex for resources and men resources for sex, and so forth.

Nonetheless you can consider an "open relationship" under the following circumstances:

  1. You're not going to have children with the woman.

  2. You don't become economically entangled with her.

  3. She's genuinely bisexual, or at least "heteroflexible" in the sense that she likes threeways, other girls, and so forth. She'll open attractive girls and bring them in.

You can mentally translate "open relationship" to "#1 plate."

If you're looking for a long-term relationship that leads to children, you should obviously break up with anyone who suggests open relationships or who has been in one in the past. But if you're looking to get laid, and you can actually pull girls, an open relationship can be fun since you have an automatic and unusual wingman (or rather wing woman), and you know you're going to get laid on a given night.

In addition, having a girl in an "open" relationship opens up the possibly of doing a lot of unusual stuff: sex parties, partner swapping, orgies. Google "Sex parties" and any major city and you'll find some interesting choices. Take advantage of them. Do everything you've ever fantasized about doing. Take Shibari classes. Watch hardcore porn together. But understand that open relationships are inherently transient.

An open relationship is predicated on a fact that is commonly obscured in the culture: There are actually two kinds of romantic relationships with women:

  1. Ones that lead to having and raising children, or

  2. All the other kinds, which reduce in the real world to "fun and sex."

If you are not in relationship 1—and if you're a guy under 25 you almost certainly aren't—then you are in relationship two. That could be labeled an "open" relationship in which the girl is kinky, fun, and brings in other girls, then so be it. Even if she confuses the two fundamental types of relationships or tries to convince you to confuse them, you shouldn't do so.

There is a reasonably good chance that "open relationship" actually just means that the girl can fuck and draw emotional and possibly financial support from two guys at the same time; if that's the case she's just another plate and you should keep looking. But many if not most guys are looking to have a good time well into their 30s or early 40s. Know your own goals. Know yourself. If you're primarily out for fun and sex pursue them accordingly and don't get hung up on labels.

Having an open relationship may be more honest: most women under age 25, and quite a few over 25, are not actually monogamous anyway, except perhaps to guys who they perceive to be of substantially higher status than themselves. Even then they bore easily—Mating in Captivity by Esther Perel should be mandatory reading for anyone contemplating a contemporary long-term relationship.

I wonder, and this is more speculative, if we'll see relationships move towards something like what Reid Hoffman and Ben Casnocha describe for the business world in The Alliance: Managing Talent in the Networked Age. The Alliance should be read by everyone in modern businesses and is too sophisticated to encapsulate easily, but the writers speculate that many businesses and employees should create realistic loyalty pacts for a "tour" of duty in a given company or on a given project, and they should remain allies even as they pursue other interests. This is actually quite close to what many contemporary people of both sexes do, even if they don't label it as such and are reluctant to admit to themselves how what they say they want and what they actually do intersect.

Perhaps not surprisingly, though, if you're in a relationship that doesn't involve living together, cash transfers, goods transfers, or marriage, it isn't likely to last. In discussing open relationships, it's easy to slip into semantic arguments because open relationships done well don't look much different than plates.

If you're already married and your wife suggests an open relationship, your marriage is already over, and it's up to you to decide how long it takes you to acknowledge that fact.