Give him another chance?

I caught my boyfriend messaging other women behind my back he had met on a dating site and had confronted him with proof which he denied (that’s the hard part for me). We have been working on our relationship since all this came out, things such as better communication again, being more affectionate, making each other laugh more again, etc, but I’m struggling to get over the fact he denied it when I had proof, some nights it’s still affecting my sleep and eating habits which I know is not good, I want to forgive him but the denial hurts.
I keep thinking maybe he just wanted some form of validation that became complacent in our relationship and we’ve been working on (doing things I used to earlier in the relationship again etc).
Thoughts?
Updates
11 mo
He has also been talking about taking me places in the future.
I asked him what our song was to see if he remembered and he didn’t, I sent it to him and he said that wasn’t it (when I have proof in messages it was the one we agreed on). I asked him if it bothered
Updates
11 mo
him not knowing our song and he knew one that makes us think of how we met we both agreed on, but had said no. He asked if it bothered me and I said yes, he asked why and I told him I never doubted myself on knowing a song with anyone before, he said we’ll pick a new one and there’ll be many
Give him another chance?
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