My crazy friend has a crush on my boyfriend and he lives with her

I have a long-winded story and need advice. Please bear with me.

My friend is kind of crazy, but our families are close, I love her, and we grew up together. I’m 29 and we’ve been very involved in each other’s family and lives since we were 8 years old.

She had problems with drugs/alcohol since high school, and it got so bad that she had to be sent away to rehab/boarding school for her senior year. Just prior to her stint in rehab, we had a huge blowout that nearly ended our friendship.

One of the many times I picked her up and took her to my house while she was on a bender, I let her stay at my house (my parents were out of town, we were 17, and my bf at the time was staying over for he first time). I was a virgin, my friend was not. When I woke up, I found my friend in my bed with me where my BFF fell asleep, and he was sleeping on the ground. I found out later that she had tried to have sex with him WHILE I WAS ASLEEP IN THE SAME BED. I discovered this right before she went to rehab, so when she came back and tried to make amends, I was weary and hurt, so we didn’t talk for about two years. When she invited me to her wedding, I realized I forgave her and I was ready to move on with our friendship. We were tight again ever since, and aside from normal bouts of drinking in our 20s, she has been relatively clean and functional since.

She’s been married for 8 years now. She set me up with her husband’s boss a couple months ago, and we’ve gotten serious.

A little about my boyfriend:

He’s going through a divorce. He had been living out of a hotel for work in my city for several months and staying in my friend and her husband’s spare bedroom most weekends in our hometown 2 hours away. He drinks a lot on the weekends, and so does my friend and her husband.

Recently, my friend came to visit me in my city and she planned to crash on my couch. My boyfriend bought us all dinner, and the drinks were flowing. We came home and had more beers, and then my friend began to complain about her marriage, and how her husband never wants to have sex with her. She always complains to me about him, and she was clearly looking for advice from my boyfriend, so I went upstairs to take a shower, and came down to find her crying and hugging my boyfriend. The hug lasted longer than made me comfortable, so I announced that I was going to retire to bed.

My friend took a swig of my gin from the bottle and said she was going to smoke a cigarette. My boyfriend said he would join her and I decided that I would not allow him to join me in my bed if he wasn’t upstairs in five minutes. He came upstairs and joined me in three minutes and I expressed my disappointment in being a third wheel in my own house. He then confessed to me that my friend had kissed him once when he was on the couch at their house. I got all the details. He said nothing happened more than the make out/him touching her chest... they both pulled away, and never discussed it. My friend did not tell me this, and my boyfriend is honest to a fault, so I trust him. When we woke up the next day my friend was gone and my boyfriend had a missed call from her at 12:30 AM. I freaked out because she had been drinking a lot and I was worried something happened to her. She drove back to our hometown two hours away in the middle of the night drunk.

I could never forgive myself if she if something had happened to her. I never thought another man would come between our friendship, and it might not be a big deal, but she never told me about the kiss. I felt it was also suspicious that she called HIM in the middle of the night instead of me before she left to drive two hours home drunk.

After discovering she was alive and well the next day, I called her to chew her out about driving drunk and told her she made me feel uncomfortable with the way she was interacting with my boyfriend/called him before leaving instead of me. I asked her if she had a crush on him. She denied it. I told her she was beginning to act reckless. I told her the only time she made me feel that uncomfortable was when she tried to hook up with my boyfriend from high school. I baited her to confess to their kiss, but she didn’t do it. I think she either forgot about the kiss because she was blackout drunk, or is consciously withholding the truth from me.

Now my boyfriend’s project in my city is over, and he is living in my friend and her husband’s spare bedroom until he finds a place. He’s dragging his feet.

Do I have a reason to be concerned? Does anyone have any advice or insight for me? I’m getting more and more invested in my relationship and I’m considering quitting my job to move back to my hometown and live with him...