He would be with her if he weren’t with me

There’s been this girl I been iffy about since the beginning of our relationship they jus seemed too close the first time I confronted him was when his phone pinged and I saw her name and she called him babe I asked him wtf was that about and he said they bestfriends and nothings ever happened I looked through his phone and I came to the conclusion that okay nothing had happened since he’s been with me, a few months past and I still had trust issues with it I look through his phone and there was a conversation where she asked if he was still with me and he said “kinda we’ve been having issues” we weren’t tho we were the happiest cause a month before that we were having issues but we figured it out.... when I saw that he said that my heart broke I thought wow is he trynna get with her even after he told me not to worry ... I confronted him broke down in front of him asking him why if I don’t don’t make him

Happy to just tell me I would understand I told him I couldn’t do it with him anymore and I walked out the car i left him crying 🚗 he sent me a whole message on how he’s so sorry that he hurt me like that he never meant to blah blah blah and he never wants to see me like that again. I forgave him cause I love him and he swore nothings ever happened later he admitted to me that they almost dated but that was his cousins ex and they didn’t want to do that to him last night I saw her name pop up again and I looked at the conversation and she was flirting with him and he was shutting it down but he said it’s wrong because he’s with me and he loves but he also said that if he weren’t with me he’d be with her ... I tried to act like that didn’t hurt but when I left his house I broke down ..should I let him go I don’t want to block that if he has feeling her her I don’t want to be the middle man I don’t want to always feel like there’s going to be something between them and I’m in the way of that ..... I love him no doubt we’ve been through a lot together he’s the only person keepin me together he’s there when I need him to be they never hang out or anything all they do is text and that’s once in a while I’m just idk what to do anymore I know he loves me no doubt but I think he might also love her and if it’s not love he at least likes her a lot