My boyfrnd of 2 years told me he had sex w/someone else when I was ignoring him and not speaking to him. due to an argument we had . He said it was one time. Why does he still want me if he cheated?

You are the only one who has been there for him for 2 years. If you leave now and break up with him then he will feel lonely. He still wants you because he does not want the feeling of losing someone. You should do what is best for you, this relationship and the future. He must want you to give him another chance of fixing the relationship. For someone to commit such an act is unfair on you. But if he shows that he wants to change and learn from his mistake. You should give him a chance but this time make sure he shows you trust.

Some people want to use other people and also have them to fall back on after having a significant, conscious slip in judgement. He could still want you because that's comfortable to at, in a relationship and with no consequences for your actions. If he was upset at you, he could've told you he wanted to talk and not go out of the agreement of the relationship. Going to someone else to fulfill the intimacy a monogamous, happy relationship does is a big breach of trust, privacy and something to think about. People would like to think they can mess up and not be penalized. It's abnormal but it's being normalized. Every conscious action one makes is up to themselves and they're responsible for it

In my opinion, there are a few reasons for this. I'll give you both of them. First, he could have realized how much you meant to him before he made this grave mistake. Obviously him apologizing doesn't take away from the huge mistake he made, but he could have had an enlightening moment and he could have realized that he loves you and needs you in his life. Second, he could have just got caught. He could realize that he made a mistake, but instead of wanting to be alone, he can apologize for what he did and hope that you will take him back regardless of what he did. Either way, I feel that you would need to see how sincere he is with saying he wants you back and that it was only one time. You need to take care of yourself first before you worry about taking care of him.