Traditional marriage vows cover better and worse; sickness and health; riches and poverty; forsaking all others... but not its opposite. What is the opposite of forsaking all others, anyway? Well, if forsaking all others is about the absence of sex (with other people), then its opposite, in our opinion, is the presence of sex (with your spouse).
We got to thinking about the presence of sex in marriage after reading these quotes on YourTango from couples who have been married for 25-plus years, on how often they currently have sex. The answer: Some of them have it multiple times a week; others haven't had it in many, many years.
Of course, sex is as much a symptom as it is a cause. Bad marriages usually lead to bad or no sex. Only if you're lucky will you still be having makeup sex after you fight... 25 years into your marriage. And decades of resentment isn't exactly conducive to post-date-night sex. Also, simply having sex a few times a week is no guarantee that you'll still be happy after 25 years of marriage. (Especially if only one of you really wants it.) And who's to say that a virtually sexless marriage doesn't work for some happy couples?
Whatever the case, it's a lot harder to resent each other when you're having sex that's satisfying to both partners as often or as little as you'd both like. There's a world of difference between sex a few times every week or month after 25 years... and no sex at all. There's a world of difference between sex that satisfies one partner, but rarely the other. Wouldn't you like to know what your spouse hopes for? Wouldn't you like to know what your partner would think if those hopes were dashed? And wouldn't you like your partner to know your own hopes?
There are no guarantees, of course. Penises malfunction, menopause strikes, bodies change, libidos wane, childbirth fucks everything up, etc. So we're not suggesting that marriage vows contain any sort of binding commitment to, say, sex every week for the rest of your married life. Besides, we think Aunt Mabel would probably have a heart attack right then and there if she heard this: "In sickness and in health, for richer, for poorer, for reciprocal oral sex and extended sensual massage, for sixty-nines and 20 minutes of foreplay..."
What you should vow, instead, is to do everything in your power to make sure your partner is happy in the bedroom, whatever "in the bedroom" means to them. Note: This kind of vow only works if both of you vow the same thing. That means compromising. But you both have to compromise. Think of it this way: If one of you wants sex every night and the other one wants it, well, never, then having sex every night obviously isn't a compromise. But in the same vein, if one of you wants sex every night and the other one wants it, well, never, then never having sex isn't a compromise either, is it?
Unlike traditional marriage vows, a sex vow isn't one-size-fits-all. Maybe your own personal compromise involves porn... or maybe it involves an open marriage. Maybe you're willing to discuss a don't-ask-don't-tell arrangement, or happy ending massages in Vegas. Are you open to kink? Role-playing? Talking through fantasies together? Maybe just the possibility of getting a new sex toy to try together every year on your anniversary. Whatever it is, we think it's probably a good idea to discuss what you're each open to before you get into a rut. And once you've had the conversation, then all you need to promise is to try to be a good custodian of your partner's desires... whatever that turns out to mean... within reason, of course (e.g. if you got married with the expectation of a straight monogamous relationship, but five years down the line your partner wants to experiment with bisexual orgies, then you are not automatically obligated to sign them up for the nearest swingers convention).
But if you're dedicated to being open-minded and communicative in your future marriage, then you might consider coming up with a code word for this sex commitment, inserting it into your vows somewhere and actually saying it out loud as part of your wedding ceremony. That way, Aunt Mabel still makes it to the reception.