I think you have a chance, IF:
- he is truly sorry and heartbroken that he has hurt you
- he is willing to openly answer any questions and provide any details you ask in relation to this affair
- he is determined to make it work
- he is more than willing to go to counselling
- he realises you will have moments where the mistrust will rear it's ugly head again because he's broken your trust. He will need to reassure you now and again by being transparent with his plans/whereabouts in situations you may not feel trusting of.
This is all still very raw for you. No rash decisions need to be made. Just look after yourself at the moment. I hope he is fighting to save your relationship