Search Results: giving up on a loved one

So I dated my ex for 7 months. My ex has a bad relationship with alcohol and is a drug abuser. 4-5 months in she got heavily intoxicated and high and cheated on me then lied about it. I took her back because I didn't want to believe the truth but from then on I had trust issues. Fast forward to 6 months in I started to have an issue with her relation to one of her ex's. Before me there was this guy she was with for a year and she kicked him out. 3 months-ish after we began dating. Before that guy she had this on again off again ex who she said was a pretty lousy boyfriend, she didn't really love him, and would only be with him to get back to a place of normalcy. They remained friends because he still had feelings for her and I would get upset that she wouldn't tell him she had a boyfriend. We got into it and had a momentary split because I felt disrespected. During that split she told him about me and he didn't seem to care. After we got back together things were good. In month 7 I got home from work and messaged her what she was up to. She said she was going to grab dinner with him to tell him about me. Naturally I hated the idea but I let her go because I can't control what she does. She texted me telling me "he thinks you're great, he's happy we are moving in together, he says you're making me a better person." She then texted me when she was home safe. She didn't tell me he came over for drinks after and they went out with old friends to do drugs. She then broke up with me after we fought about it giving me the whole "Its not you its me". The next day she was back in a relationship with him (Pretty sure there was overlap). We work together so its hard seeing her replace my photo in the back of her phone with his and seeing come in with a big ass hickie on her neck (she's 29). Im wondering though, was I the rebound or is he the rebound and she went back to him for temporary comfort. We dated for 7 months and she said she wanted to make a family with me