My boyfriend wants me to stop seeing a friend I made on grindr

r/

Hi there, sorry about the length of the post, tl;dr at the bottom — I kinda got carried away. (I used AI to correct any grammar mistakes I could have made)
My boyfriend and I are really happy together and moving forward in life (we have our ups and downs, but we both love each other to death).
We’ve been together for 2.5 years now, and because we’ve spent a big chunk of our relationship long-distance, we decided to open it up while we were physically apart. We set clear rules and communicated a lot about it. He saw people, I saw people — everything was fine.

Unfortunately, he caught something. And as if catching an STD wasn’t stressful enough, he’s borderline phobic of anything even remotely needle-adjacent, so getting tested was a whole ordeal for him.
I thought getting tested before coming back home to me was a given, but I guess he hadn’t thought of it beforehand. When I reminded him to get tested before his return, he decided to stop seeing people altogether. He told me he had no problem with me continuing to see others, though.

Since around September, I met a guy on an app — let’s call him B. It was supposed to be just sex, and then we’d go our separate ways, but we actually got along really well, so we started hanging out even without sleeping together. I genuinely felt like I made a new friend, which my boyfriend was okay with at the time.
B and I hung out at least once a week, sometimes going weeks without any sex. I was only mildly attracted to him physically and not at all emotionally, so the friendship developed pretty quickly. On top of that, he’s not romantically interested in men at all — he’s just into the physical part.

I started feeling like it was unfair that I got to have fun while my boyfriend didn’t have the same freedom, so I asked him several times if he was really okay with it, and told him I didn’t mind closing the relationship. He always reassured me that he didn’t mind, and that I could keep exploring (he knows B is the only guy I saw).

Now, a few days ago, I asked him if he’d like me to stop seeing B, and this time he said he would. I had kind of assumed that once we closed the relationship, I’d still be friends with B and we could hang out platonically.
I asked my boyfriend if that would be okay, but he said he’d rather I didn’t — he’s suddenly feeling jealous.

I completely understand his reaction. He’s never met B and doesn’t really know the dynamic firsthand, so I get why he might feel insecure. I would never force him to let me see B again if it makes him uncomfortable.

I guess my question is this:
Would it be fair for me to try and convince him that there were absolutely never any romantic feelings between B and me, just so I can keep the friendship?
Maybe once he comes home, I could introduce them — like I do with my other friends?
Although I realize that might be an awkward, “Hey, that’s the guy who f*cked me while you were away, btw!” type of situation…

I’m just bummed about potentially losing a friend, and I’m trying to figure out a way for both my boyfriend and me to be as happy as possible in all this.

TL;DR:
My boyfriend and I opened our relationship during a long-distance period. I formed a mostly platonic friendship with a guy I casually hooked up with (B). Now that my boyfriend wants to close the relationship, he also wants me to stop seeing B entirely, even platonically, due to jealousy. I respect that, but I’m sad about losing a friend. Would it be fair to try and reassure him so I can keep that friendship alive somehow?