Made a mistake that I am struggling to fix

Me and my boyfriend have been exclusively dating for about a month. We met on a dating app where we had both being dating around prior to each to meeting each other. I am absolutely crazy about him and have been invested in him since we went on our first date, there was an instant connection from the beginning. I was on two different dating apps before we met, and I deleted them both (or so I thought) when I felt like things were going to become exclusive between us. This is an important detail. Yesterday we were on the couch watching football when I decided I wanted to check my horoscope on an app that I pretty rarely frequent. It was buried on the last slide of one of my app folders, and when I got there, I was a surprised to see one of the old dating apps still on my phone. At the time that I was actively dating, I didn’t frequent this one as much because it was more of a place to find hook ups, so I had the notifications off all this time, explaining why I had no idea it was even still there. I deleted it right away. I have never had any kind of want or desire to cheat on my boyfriend or talk to other men and I never have. I value our relationship so much and I truly have always felt like we have a very special connection and I would absolutely never do anything to jeopardize that. I can’t imagine putting him in that kind of position. He ended up seeing me delete the app while were sitting on the couch. He has a great sense of humor and joked about it a little later, where he said he believed me and it was okay. I had never felt so awful in my life, because I know how terrible that would look down and seeing me delete a hookup app on my phone. Later when we were going to bed, he was being very quiet and I knew something was wrong. He just said “do you promise you weren’t using [dating app]?” and it just broke my heart. I told him he could look through the app if he wanted to, and I tried explaining myself because I knew how bad it looked but he didn’t think I needed to explain myself. He kept saying “I believe you, it’s okay” but things just still didn’t feel right afterwards. I explained that I would never do anything to compromise our relationship and it was truly such a stupid mistake on my part and that I know how bad it looks. I started to tear up and get upset because I was just mad at myself, which made him feel bad and start apologizing. He just kept saying “I know, I believe you and it’s okay” but I just couldn’t help but feel like things still didn’t feel right. He goes to work very early in the morning before I wake up so I haven’t had a chance to talk to him again yet. I am drowning in guilt even thought I didn’t actually *do* anything, I just feel so awful for putting him in a position like that. I’m also having thoughts like “does he actually believe me or is he just saying that?” but at this point i’m unsure if that’s just me having anxiety or if I really feel like he internally doesn’t believe me. Things just feel off now and my biggest fear is that I’ve ruined everything. I think having an outside perspective would help me think more clearly.

Acting guilty is not good. You've apologized, move on. If he's got trust issues, that's for HIM to fix, not you. Nothing you do or don't do will fix him. He's not a project for you. Serious emotional/mental issues need professional help. You've only been exclusive one month. The guy I'm with now, he was still on a dating site maybe four months after we started dating. I was - how to put this - perplexed? - because we were seeing one another two or three times a week. Every time we concluded a date he asked, "When will I see you again?" About the time I started to survey my male friends about this, he closed his account. I don't know why it took him so long - maybe he just had other things to attend to. We've been together nine years.

If he believes you, that you weren't actually using the app while dating him, then he could be upset about something else. For example the realization that you used an app for "hookups". Guys don't like the knowledge that their gf/fiance/wife had a number of 1 night stands.