I am a bi female in a heteroromantic relationship with a man I thought was straight. Recently he admitted to sexting a few girls early in our relationship and one currently who is his male friend.

He expressed to me that he and his friend had been intimate in the past but he worried I'd leave him if I knew he was bi too. I expressed to him that I'd be extremely hypocritical and an asshole if I left him or didn't date him over his sexuality, especially since I'm bisexual. But I was concerned that he was still sexting his friend.

Ever since I found out though, I can't stop thinking about them together and it's making me extremely hypersexual (I've got a mental illness and it's a comorbidity). I keep thinking/dreaming about eating out/fingering girls, and having a MFM threesome with my partner's friend so I can watch them together. They only ever gave each other bjs and hand jobs so never penetration but I've even been fantasizing about watching them fuck each other.

I love my partner and we aren't super strict about monogamy so the idea of potentially having some fun with other people is not off the table. But now it's like I'm obsessing over it to the point that I can't seem to get it out of my mind.

Is this a kink or am I just dealing with my partner's sexuality change weirdly? I'm not sure how to fully process that he's bi tbh. I mean it's sexy to me obviously, but is the reaction more unusual or is it normal to over-fantasize about your partner's new orientation affiliation?

But he hasn't expressed interest in being pegged or inviting his friend for sexy fun so idk how to proceed. And is it wrong how badly I want to fuck a girl now, I'm having a sexual existential crisis.