So let me begin with a little backstory. My fiancé is 26 years old. She started drinking and smoking at a young age and eventually got into heroin. It got to the point where her parents sent her to rehab in SC when she was around 21/22. I met her not long after she finished rehab in 2012. At the time she was replacing heroin with alcohol. Around 2013/2014 she moved into her own place and I eventually found out that she was drinking every night due to loneliness and her depression. We moved in together April of 2016. At first everything was fine. We'd drink every once in awhile but then in September she started binge drinking again because I picked up a second job and wasn't home as much. It spiraled out of control until eventually she went back home to go to rehab again. This is her last week in rehab and she's been sober over 40 days. When she first moved back we were fine I tried to be as supportive as possible. I was supposed to visit her but due to lack of sleep I didn't. She met this kid at rehab and started texting him. I knew something was going on but she kept denying it. I found out 2 days ago that she was sleeping with him. I don't know why but I forgave her and want another try with her. (She's the love of my life) Currently she's confused on what she wants to do and has no real course of action. She says she loves me and cares for me and we continue to text but she's also hanging out with this other guy(He was a heroin user). My question is what can I do in this situation. I know she making a mistake and she's filling a temporary void In her life. Is there any way that the loneliness is fueling this? Should I keep talking to her and working on our relationship? Please no negative comments. Im going through a hard enough time as is and need all the support I can get.