This might be a little vanilla for you, but I thought I'd chance it.
My boyfriend and I are in our mid-20s, and I'm fairly confident that we'll be married at some point. I'm only the second girl he's slept with, though, and the only girl he's had an orgasm with. I've had a few more partners. I genuinely feel like he should have sex with other women before committing. Do you think the numbers matter? Is he going to wake up at 45 needing something different? Is there any way I can get him to have sex with another woman and not feel like he's cheating on me?
Commitmentphobe (for him)
Well that last part is up to you, isn't it? If you're going to feel like he's cheating even though you pretty much ordered him out the door with your phone number and address pinned to his underpants, there's nothing I can do for you. You're going to have to decide which is more important to you: lifelong fidelity or knowing he's had a look around and still chose you. Without a time machine at your disposal (oh, how I wish I had one, for so many reasons), you're not getting both.
Here are two facts, make of them what you will. (1) Americans, on average, have not had anything like the number of partners racked up by unmarried characters on any sitcom you might watch. At last count by a trustworthy source, half of all adult Americans had had three or fewer sex partners over the course of their lifetimes. More than your boyfriend/husband will have to show for it on his deathbed, should he neither cheat nor obey your order to go out and slut around first, granted, but certainly not what you'd expect from the way people do go on. (2) If he's going to get bored at 45 and need a little something different, that's going to happen whether or not he does the homework you assign him at 25. If it helps, when the data for the landmark "Sex in America" study were collected in the early ’90s, it appeared that the vast majority of married or cohabitating couples were in fact faithful to each other, something that, again, you'd never guess from watching TV or movies, or even reading popular or literary fiction.
And, anyway, cheating is not the leading cause of divorce. Many studies point to money or plain old "incompatibility" for that, and not necessarily sexual incompatibility — although that does count. There is even some research showing that "being very unhappy" needn't cause divorce in and of itself: 86 percent of couples who reported being unhappily married in the late ’80s described themselves as happier five years later, and indeed most called themselves "very" or "quite" happy by then. It seems that the best indicator of whether a marriage will last is whether the couple wants it to last and is willing to stick it out.
I do digress and I do apologize, but I guess what I want you to get here is that projecting your worries into the future (there's that time machine again) is not necessarily the best use of your time while you're young and happy and have a wedding to plan. If you've made the offer ("Sure you don't want to go out and spread it around a little before we settle down?") and he is still not interested, you might want to consider just being glad he's so satisfied with you, and start picking out china patterns.