Should I believe my boyfriend or another girl?

Anonymous
I found out that while I was 7 months pregnant my boyfriend had met a girl at the library at his school and had began to occasionally talk/flirt with her on facebook and on the phone. I talked to him and he admitted to talking/flirting with the girl and claims that is all that happened. I read the messages and they were mostly innocent nothing about sex. He would just comment in ways such as you look like a mode I in one message and the rest of it was hey how you doing etc. I talked to the girl over facebook and she said they had had sex. He denied that automatically when I told him and claimed he had told her that she was developing too much feelings for him at one point and she got mad about it. I read a message that he wrote that said things like I miss you I wanna talk call me I was in a tough situation and it also said to her I guess you be mad @ me off and on is that why you walked off in the library today.I asked the girl and she said she has no evidence that they slept together because she told him not to talk about sex in messages because she thinks sex is bad? Parts of what she says don't make sense and I don't know if I can trust her or not. I would like to believe my boyfriend but it's hard to trust after something like this happens.Who should I believe and should I give him another chance?
Updates
+1 y
He seems sorry and like he regrets the situation but I just hate that the girl says something different than him. I just don't wanna be too naive, but the girl could be lying also so I don't wanna automatically believe her over my boyfriend.
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+1 y
She also messaged me and said he had called her rite b4 I messaged her and asked her not to tell me anything.he said he had called to give her a heads up that his angry girlfriend was gonna call, to be courteous since they hadn't spoke for awhile.
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+1 y
that was something that caused even more doubt.
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+1 y
what do you mean by and probably more I don't get what you meant fernando
Should I believe my boyfriend or another girl?
17 Opinion