Just found out she cheated
I found messages on my girlfriends phone where she's been talking to her ex and they were sexual in the messages. I confronted her about it and she denied sleeping with him, eventually I set up my laptop to record her when I'm not in the house and I got in the recording her talking to her ex on the phone basically admitting to sleeping with him. I confronted her again before playing the clip to her and she denied it again. After playing the recording she started crying and confessed to sleeping with him and said she was scared to tell me the truth. She would leave me with our 2 month old baby and tell me she's going to sort out her college registration, only to find out now that she was going to sleep with her ex while I stayed at home with the baby. She's been begging for forgiveness and for me to give her another chance, what should I do?