I'm engaged to a wonderful man but our sex life is on the rocks because I have medical issues that make penetrative sex very painful and we've put PIV on hold while I go to different doctors and physical therapists so I can work on it. We've talked about opening our relationship so he can find relief but it scares me. Mostly because I can't handle the fact that there's something I can't give him that another woman can. If our sex life was healthy and all we wanted was to try new things with new people, I'd be fine. But the idea of him having sex with another woman and suddenly realizing what he's been missing by being with me is so scary. Are there things we can try in the bedroom to simulate P&V to help tide him over? Or are there ways for me to turn down my ego and accept that I can't be everything to him?
Other Penetration Evidently Necessary
Like I'm always telling people who worry they're "not enough" for their partners—something I typically hear when someone is stressing out about their partner's porn—you aren't enough. You can't be "everything to him," OPEN. Even if you weren't currently struggling with (and hopefully overcoming shortly) a medical problem, you're not enough for him. And he's not enough for you and I'm not enough for my husband and he's not enough for me. Settling down always requires a little settling for. Of course you shouldn't settle for abuse or contempt or a Trump voter—no one should—but no one gets everything they want in or out of bed.
All that said, OPEN, I don't see any reason to open up your relationship at the moment. Or ever, if an open relationship isn't what you want.
Penetrative sex on hold for the time being? Or, to be more specific, PIV (penis in vagina) sex on hold for the time being? Then get busy exploring all your non-penetrative/non-PIV options—oral sex (which can, of course, involve penetration), sex toys (including toys for men that are designed to be penetrated), outercourse, frottage, fantasy play, anal sex (you can explore penetrating him) cyber sex (which, yes, you can have with an IRL/in-the-same-apartment partner). There are a million different/non-PIV ways you can provide your wonderful man with "relief," OPEN, and a million different ways he can provide you with relief. If your medical problem doesn't prevent you from enjoying other kinds of sex, you can still give and receive pleasure.
Straight couples/people often default to penetrative sex because too many believe "PIV is sex and sex is PIV." (Some gay men similarly default to anal.) But sex is so much more than just penetration and/or PIV—as my regular readers are hopefully aware!—and now would be a good time to expand your repertoire. You two will hopefully emerge from this experience with a better understanding of your bodies, your capacities to give and receive pleasure, and far a less PIV-centric notion of what "straight sex" can and should be. A medical problem/crisis is never fun, OPEN, but with the right attitude you could emerge on the other side with a stronger connection and a much more varied and satisfying sex life going forward. Good luck!