Am I being gaslit?

Hi guys, I’ll try to make this short.

I’ve been with my boyfriend for about 6 months now. He has narcissistic traits and I have bad anxious attachment.

He went on a trip this August and I offered him to be open while he was away (I know it’s bad because it’s just easier than trust) and he cried and said he couldn’t believe he wasn’t enough for me. That was enough for me to step back and try to trust.

While he was away I found him on Grindr.. his profile said: not looking for sex, just friends and selling tickets to a concert. I confront him about it and begged me to believe it was just to sell the tickets and to buy weed. Deleted immediately after he got it.

After that, he confronted me about new people I followed (most female friends), and from that moment I started paying attention to that too and noticed a guy. I asked him about the guy, he said it was a friend of a friend.

He checked my phone when he got home and obviously didn’t find anything because I’m not the cheating type and said: if you check my phone I’ll break up with you.

Turns out this guy he met at a bar, invited my bf a drink and talked for a bit. The guy put his hands on my bfs leg and my bf decided to leave and call me. (That’s his story now, before he pretended not to know who he was)

I asked him to show me his messages with him and there was nothing, it was empty, it just said: “invitation sent”. But he still swears he never texted him. (He unfollowed him after I made it clear it made me uncomfortable)

He gets really sad and defensive when I don’t believe him but he makes it really hard for me. He swears he’s faithful and that he doesn’t want threesomes, or group sex, or open relationship. Which I’m ok with AS LONG AS it’s reciprocal.

I know it’s toxic. I just want to know if it’s me who needs to work on my insecurities.

Some things about him:

He is literally declining amazing job and study opportunities to come continue our startup together, planning family trips with his family and mine, planning lots of stuff to do together, he’s actually really sweet and loving, except for when he needs space, he asks for it and comes back to me on his own. He’s amazing with his mom and with mine.

Honestly I’d rather have an open relationship than feeling like he’s lying, but he denies everything.