My partner and I are in our early 30s and have been together for 6 years. I'm a cis-gendered female and my partner is FTM and began his transition last year. Up until that point, we had a fairly vanilla but satisfying and regular sex life. We both started to want kinkier sex, more variety, and some agreed-upon openness but had yet to really do the work to get there. The changes our relationship have gone through since his transition started though are so drastic I'm having a hard time wrapping my head around where to go from here.

My partner expressed interest in hooking up with men after starting T six months ago (something he had done when female-identified but hated). I was begrudgingly ok with this, not because I'm opposed to fun outside our relationship, but because he doesn't currently have any desire to have sex with me. I know I can pursue sex outside our relationship because we've always had an open-door policy, but I don't have any desire to be in a purely companionate relationship at age 30. The fact is, the only sex he seems interested in having is secretive, unprotected sex with old (60+), hairy, male strangers off Craigslist. I have nothing against old hairy men (although definitely not my cup of tea), but using protection and disclosure to each other were on our list of boundaries. He only admitted his behavior because his lies became too big for even him to keep track of.

He's noticeably less verbal and unable to identify his own emotions & intentions since starting T. He doesn't have any idea why he wants what he wants or if this is just a phase. Is it possible that T has permanently changed my partner's sexual orientation this much? My compassionate, emotive, ethical partner who was always so GGG and pro-safe sex seems to have turned into, well, just some gross dude. He identifies as pansexual but is really only pursuing the grandpa demographic which I clearly don't fit. I should also add that my partner has struggled to maintain his sobriety & has been dealing with depression since starting T. I feel utterly heartbroken and confused about who he has become.

Partner's Always Playing Around Sexually

Your question reminded me of a This American Life episode from—holy shit—nearly fifteen years ago. The theme was "Testosterone," PAPAS, and one of the pieces featured an interview with Griffin Hansbury, a trans man, about the changes he experienced when he started testosterone:

The most overwhelming feeling is the incredible increase in libido and change in the way that I perceived women and the way I thought about sex. Before testosterone, I would be riding the subway, which is the traditional hotbed of lust in the city. And I would see a woman on the subway and I would think, she's attractive. I'd like to meet her. What's that book she's reading? I could talk to her. This is what I would say. There would be a narrative. There would be this stream of language. It would be very verbal. After testosterone, there was no narrative. There was no language whatsoever. It was just, I would see a woman who was attractive—or not attractive. She might have an attractive quality—nice ankles or something—and the rest of her would be fairly unappealing to me. But that was enough to basically just flood my mind with aggressive pornographic images, just one after another. It was like being in a pornographic movie house in my mind. And I couldn't turn it off. I could not turn it off. Everything I looked at, everything I touched turned to sex.

Hansbury was on a really high dose—which wasn't explained in the piece—but, yeah, T can really change a person. It didn't change Hansbury's sexual orientation (he was into women before and after his transition), but it's not unheard of for a person who is transitioning from female to male to also transition from "into women" to "into men." Vice looked into the phenomenon a couple of years back:

For transgender men, injecting testosterone is a fundamental part of their transition. Bone mass, voice pitch, energy levels, temperament—the list of physical and psychological attributes it has the potential to alter are exhaustive. It's common knowledge that testosterone ramps up the libido. But for some trans men, it doesn't just heighten their sexuality, it shifts it altogether.

"Prior to my transition, I definitely considered myself a lesbian for sure," says 33-year-old Will Krisanda. "I was primarily attracted to women, but now it's completely shifted. I'm finding myself more attracted to men. After about a year [on testosterone], I started to accept my sexuality as a bisexual. That took me by surprise, because I've always been more comfortable with women. Testosterone is a powerful thing that's going into your body and it has some very interesting and permanent changes."

Though he identifies as bisexual, Krisanda is currently only interested in exploring romantic and physical relationships with men. Even if his friends offered to set him up on a date with a potentially well-matched female, he says he'd probably decline the offer. In less than a year, Krisansda had gone from exclusively dating women, to exclusively dating men. His experience isn't an uncommon one in the female-to-male (FTM) community.

So, yeah, going on T can really change someone.

But while Hormone T may explain your partner's sudden desire for Grandpa D, PAPAS, it in no way excuses his behavior or his deceit. Your partner's (initially undisclosed) unprotected and risky sex with daddies, granddaddies, polar bears, etc., is grounds to end this relationship. Not only is your partner growing in a direction that's taking him far away from you, he's doing so unsafely and with seemingly no concern for your health or emotional security. Or maybe he self-servingly thinks your health isn't an issue here, since you two aren't having sex. But the collapse of your sex life is also grounds to end things, PAPAS, since you're not interested in being in a companionate relationship with gay gerontophile.

So. Yeah. Your relationship appears to have DTMFA written all over it.

Buuuuuuuut... your partner, just six months into his transition, is in a delicate place. He needs to speak with his doctor and with a therapist—and disclose all of his recent troubling behavior to them, along with his post-getting-on-T depression and sobriety issues. And you're in a good a position to push him to get help, PAPAS, by making it a condition of staying together for the moment. You don't have to stay with him forever; transitioning and being on T doesn't give someone a free pass to be awful to their partners (or anyone else), PAPAS, and agreeing to stay with him for the moment doesn't obligate you to stay with him for the rest of your life even if he does get his shit together. But if you can leverage your presence in his life right now to get him to get himself the help he clearly needs right now—help a girlfriend can't provide on her own—you'll be in a better place, logistically and karmically, to transition yourself out of this relationship if that's what you ultimately decide to do.

It's up to you, of course, and you have grounds to DTMFA. But he's likelier to get the help he needs if his partner pushes him to do it, PAPAS, rather than his ex. Since you're not having sex right now (a blessing in disguise), you're not in any immediate physical danger from his online/offline activities. If things don't stabilize—even if the do—you can still end the relationship. And who knows? Getting him the help he needs may restore your compassionate, emotive, ethical partner to you. Good luck.