My fiancé. Is he gay or bi? Or simply just idk curious

My fiancé and I went to high school together we were really good friends. We dated after high school for a short period of time but due to his video game playing, multiple female friends, masturbation, gay male friends, and inability to take on responsibility we broke up. Everything above was just too much for me to handle at the time and I felt he was secretly hiding his attraction men. I had a nagging voice and gut feeling that something was just off. Well fast forward three years later we rekindled the flame and both talked about what we could of and should have done differently. Well our sex life became totally different this time around we had always had intense sex but now he was hinting at anal stimulation.... I went for it. Why not? It was hot at first and I felt dominate. I licked it and even used my fingers while giving blow jobs. Well again that gut feeling came back. We were sitting on the couch one day and his gay male friend sent him a message on his PlayStation saying " hey I was thinking about you today miss you love you :)"... it jut didn't feel right he automatically got a guilty kinda look on his face. He said that the guy just does that and he doesn't know why he keeps talking to him like that.... I asked if he ever told him not to he said no. I let that go but then I decided to check his PlayStation messages and found that he was trying to communicate with a transgender asking if they could catch up🙁🙁 again I let it go. Well the last thing that happened included him confessing to watching gay porn because he was curious and also meeting a couple on tinder when we weren't together. The couple was husband and wife and he said the man wanted to have sex with him in front of his wife but he felt too awkward so he left. I just don't believe anything anymore. I'm so confused. I don't care if he may be curious... bi.... gay whatever the case may be but I just feel i have a right to know what I may be potentially marrying. I've asked him if he was gay attracted to men etc and he told me that he got off to gay porn before but he would never sleep with a man. 😒😒 I don't want a time to come where we have kids and daddy ends up being curious and experiments with someone. It's just something I couldn't handle and I don't know if I'd stick around. Someone help me what do you think? What should I do? I've already tried asking him but I just feel he's not being 100% truthful. I know it may be uncomfortable for him so I don't want to hound him about it causing him to be even more secretive.

Update: there is just so much 😞😞 when I actually sit and think about all the signs it's so sad. When we are out in public it's his mission to point out every gay guy that walks by. " oh he's gay" that's what he says. One day I was finally fed up and I just said ok and who cares so what. He looked dumbfounded... but why are you pointing out every gay guy? It's so hard to be 100% there for your man or person you're with when deep down you feel there is something being kept a secret from you. Sex has become difficult I have to completely zone out to even get in the mood because I just keep thinking about the stuff he's told me... there's more but I haven't shared yet