Help please

A couple months ago I found out that my husband had been texting this girl and I went through his phone and found the messeges. I was mad but I didn't worry to much because the conversation was somewhat normal. However he was telling her to stay warm because it was cold outside and to me that was like what why are you saying those things. Anyway I went to her Facebook and I new what she looked like. I play soccer and there's this girl that looks a lot like her so I always bother him with that. I found out that she has the same name as the girl my husband was talking to. I ask him is she the actual girl he was talking to, he avoided my question but I asked again and he said yes. I was so mad because I've been playing by her this whole time and he hasn't even said a thing. I came crying because I felt so hurt and when he was trying to calm me down I asked everything I had to ask and he told me they've kissed before when me and him were going through something. But at the same time he was still begging me to stay with him when he was over there kissing her. We have a daughter and we've been together for 6 years and married for almost one. The thing is that this has been dragging for so long because he was just texting her a couple months ago. I don't know what to do.