Having a better relationship

My boyfriend and I have a pretty good relationship. We have our fights here and there and i have bad trust issues. A while back we had broken up for like a month or so. Well in that time we both downloaded tinder. When we got back together I deleted mine. And I had assumed he deleted his. I had to go to the ER one night. And while I was sitting there with him. I saw tinder on his phone. I obviously confronted him and he said he forgot to delete it. So I asked to see the messages. And the last message had been a few weeks before we decided we’d give it another shot. So the other day he asks me to send him some pictures of him that i have taken to put on his Facebook because he’s doing a thing through his job and a lot of the vendors/sponsors go off how active you are on social media to see if you’re the right fit. He’s active he just doesn’t post a lot of pics. So i send them to him and then yesterday comes. I saw a girl on his snap which kinda bugged me and I asked about. Well my anxiety and trust issues kicked in. So I started thinking maybe those pictures weren’t for fb. So I downloaded tinder and saw that he had added two new pics to his profile. My heart dropped and I screenshot and sent them to him. He immediately called me I put him on speaker to let my friend listen to see if she thought he was lying or being genuine. He sounded aggravated but not mad. He was like I have no reason to do that that was from months ago I changed the pictures yes and I shouldnt have. But I didn’t message anyone you saw that I just didn’t know if things were gonna work out with us and i just forgot to delete it because i haven’t been using it. No matter how many times I asked the question differently his story never changed. But it wasnt rehearsed either. I can always tell when he’s lying. He wasn’t doing any of the normal things when he lies. My friend said “I honestly think he’s telling the truth, the tone in his voice sounds confused and hurt but also like mad because you called him a liar. No one likes being called that.” So I believed him which on my part everyone is going to think is dumb. But that’s why I had someone else listen so I didn’t seem like I was defending him or trying to give him the benefit of the doubt. She and another friend think he’s telling the truth and i just now thought about him doing it and caught it months later. My question is how do I make myself better as In not letting my trust issues and anxiety over rule everything to where I question him everyday about it. I believe him but my anxiety gets the better of me and I just wanna know how I can manage it and have a better relationship with him. I don’t handle fights very well either. I get extremely pissed and I bitch a lot or I cry a lot. I just want advice on how I can better handle situations after stuff like that or any fights.

!!!! He uploaded the new pictures before I ever saw he had it while I was at the ER he didn’t upload them recently !!!!!

***** I’m awful at typing rn and really explaining because I’m at work******