Once a cheater, always a cheater??

Ok so I’ve kinda been chatting to this boy for a bit now. I do like him, he’s nice to me and hasn’t done anything to make me think otherwise. However I’ve just found out that he cheated on his ex girlfriend. I found out through friends, questioned him on it and he admitted it. He said he’s not the same person anymore, he was very drunk and knows it was wrong. I’ve known for a while now anyway that a lot of people think he’s “ cocky” and fancies himself a bit, and tbh I do agree with it. But I just wanted to give him a chance. However this has completely thrown me off more, what do I dooo?? Give him a chance or just sack him off now? 😭