What would you do if you were me?

My boyfriend and I got in a fight. A little back story for you ladies. My bf has a baby’s momma, and he used to tell she’s not an issue, you don’t need to worry about her, there’s nothing ever going to happen between us, I don’t want her. So one night I had a gut feeling and I went through his phone and to my surprise I see flirty texts, she was sending him sexual memes and they called eachother babe twice (I counted). This was hurtful, being told not to worry about her and I see all that broke my heart. Our relationship was rocky for a month or so and decided to forgive him. He realized he was wrong and apologized but said I know the apology won’t do anything to what you’re feeling now and he was right. So now I saw him and a girl DMing eachother. She always initiated the conversation and he’d reply. He told me that his friend used his phone to dm her because the phone was dead so he didn’t see anything wrong with it. He even texted his friend to ask him about the DMs and showed me. Doesn’t mean I believe him fully but I do know how that friend is. No where during the DMs did the friend include his name. She’d continue to dm him and now my boyfriend was replying. So today I see this. Which I think it’s disrespectful and called him out on it. When I asked why would you make a comment like that? He said I wasn’t thinking. 😑 like wtf. Then goes on and says I fucked up. So now I’m like idk what to do. I don’t want to you love an excuse but I do love him but I don’t walk to be going through this issue every time. Someone who cares for me and states that they love me should show me otherwise and not hurt me. In my mind a break would be so bad. Oh and our 1 year is this Sunday too, which means nothing now. Help