Confused

Ok so my ex and I dated for 7 years. We broke up in May. I dated someone else and so did he. We hid it from each other (I don’t know why, maybe we didn’t want to hurt one another idk). We have be absolute best friends for years. We have been friends since we were 14. Anyway the girl he was seeing is pregnant, she posted it to Facebook even though he asked her not to and that’s how I found out. I was absolutely devastated. Beyond broken. He didn’t want to tel me because he knew it would kill me. A way, we coach a travel softball team are together so we agreed to meet at his place to discuss what to do with the team when he leaves for the army. Well we started talking and we realized neither one of us were over each other. We were just too hard headed to admit it. Anyway I ended up staying the night, we said we loved each other. The next day he was having a going away party as he left for basic that Sunday. He asked me to stay for the party. I said yes because we had an amazing night and I am apart of his family and have been since I was 14. He told the girl (they aren’t official) I was coming and she came anyway. She was all over him begging him to hang out with her etc. well later that night we agreed that we wanted to try and get back together. So he told her. That he will be there for the baby (she didn’t tell him she was even pregnant until she was 5 months) (she is 19 with a one year old already. We are both 25. I am a nurse and he just joined the military. She cried and said why would I break up there family. He is an amazing man and he will 10000% be there for his child, but that doesn’t mean they have to be together? She won’t give up. She tried kissing him, wouldn’t leave his has after the party, tried spending the night, told the recruiter the next day she is the girl friend, keeps posting on Facebook he is her boyfriend. But before he left he told her him and I were getting back together. We are getting married (we were engaged when we broke up). She shows up to his families house unannounced, she threw my pictures in the floor at his families house, etc. I guess I’m just annoyed. I don’t know I’m just venting. No rude comments