My girlfriend cheated on me with her ex and lied about it
I been with this girl for almost two years and we did talk about getting married also. I loved her and she always said she loved me too. She started getting phone calls from her ex and walk outside to talk to him. When she came back she deleted the number. So i watched for a week doing that almost every day. Until I went online and checked and found out the number she was talking to and deleting was from her ex. I found out that she was talking to him almost every day. I stayed two months without telling her I know hoping she would change, but she kept doing it. In the end i confronted her about it and she told me that they were talking about their daughter together. Then a few months later we had an argument. I went to sleep and I woke up she wasn't there. After looking for her and calling friends and family, no one knew where she was at. At 930 pm she called and told me she was at her ex's house. I went and picked her up. She swore to God and her dead son that she won't do it again. A week later I was still hurt with what she did and I told her I was leaving her and I went to work. I said I am not coming back home. I came in the night and she's not home. So I started calling her and she finally answered and told me she was at a good friends and was going to stay at a hotel. I said please let me see you and she hung up the phone in my face. Two days later she called me and told me to come to the hotel and talk. I went there and we solved our problems. I asked her did you cheat on me or see your ex. She swore again no I wont do that to you. I believed her even though i had a strong feeling she was lying. So i took her and her kids to the house. We were back happy for about 3 months. Three months later I found out from her brother that she lied and did stay with her ex husband the first night she told me she was at the hotel. So I waited for six months waiting for her to tell me. Finally one day her ex texted her when i was next her and said it. I told her i know about it and at first she still denied it. Finally she told me the truth and admitted that she did stay with him and have s** with him. She told me other times that she meet him and kept it from me and that she had s** with him the first week we were together. She also told me one time she showered at his house and he walked in on her. She told me after the time at the hotel she realized how much she loves me and doesn't want to be without me and she did change. She said she hasn't done anything wrong for the last nine months. What should I do? Even though she knows I hate lies that is what killed the most trust is lies. Should I forgive her and stay with her or move on?