Can I forgive him?

💗 lucky lady 💗
My husband tried it on with one of my best friends and I can't get past it...
We were out on a night out that was pretty drunk and messy but we left and went home together.
I then saw messages on his phone to her that basically went like this:
Friend : come to mine, answer your phone
Husband: I can't Emma is here!!! I'm outside yours, too late gone
Now my friend had pulled a bloke that night and was actually asking us all to go back to hers not just him!!
When I saw it I couldn't work it out and left it for months. Recently however it came out in an argument and he actually thought she was asking him to go with her and the worst part is he would have probably gone. She was my f*cking bridemsaid!! As if she would have gone near him anyway!
Because the time has now past I feel conflicted as I've indirectly forgiven him but I can't stop thinking about it and it's making me feel bad towards my friend who didn't do anything wrong at all!! 
Ahhh help me get my head around this?? What should I do girls ??