Boyfriend cheated with a male, now he is seeing a transgender woman. Confused

This is a long and complicated situation so I appreciate anyone who takes the time. So I was with the same boyfriend for about 4 years, It started very young and kept getting better as time went on, we grew together and cared for each other, we would work through anything and I knew in my heart that it was worth it. To get right to the end of things, we had a home together, I was at this point mainly paying for us to live but he had done more than his part in the past and I didn't feel used or under appreciated once. What's some money when you feel safe, content, cared for, eager to move forward together. We ended up getting a room mate to help out with bills. A male (who we will call Mark) I had attended high school with. After a few months I suggested we move into a nicer/bigger house, and they were on board. My name went on the lease as well as my boyfriends. The months we had there I was getting very frustrated because my boyfriend would be up late in the living room with Mark, until 2-3am being loud and having a good time, which was right above where I slept and I worked early in the morning. I kept to myself for a long time but I just didn't see it as normal. On two occasions I went upstairs to ask them to quiet down or to get water and they were cuddling on the couch, I wasn't particularly concerned about it, it was actually cute/funny at the time. This was the first red flag. I spoke with my boyfriend about my feelings towards our room mate and expressed that I wanted to ask him to move out. This was for other reasons besides them spending a lot of time together. I was happy to see them as friends. He convinced me that we just couldn't afford it and that we could talk to him about the issues and they would get better. I gave it a chance. I continued to get frustrated because no one helped out around the house as much as I wanted, Mark was using hard drugs despite us having caught him several times and told him that we weren't okay with it in our home, was being very suspicious and taking things as he pleased from us that we didn't offer him. I couldn't kick someone out who was struggling with their stability so I tried to get him to confide in me about what was going on. I was very cruel at times but I had lost all respect for him, and wanted nothing to do with him. A few months later a good friend of mine was supposed to move in with us from a different province so we moved into a new house with an extra bedroom. Things were the same, I continued to leave for work before sunrise and got home around 6, I was never around. Things seemed weird. On new years I came home with a bottle of wine and wanted to spend time together with all of us, and something was up. Mark wouldn't look me in the eye, my boyfriend was being overly nice and loving. I asked what was going on. Nothing, We ended up going on a drive just the two of us, where he told me he cheated on me. I thought it was a girl from work, my friend (female) who lived with us, and I was enraged. He told me it was with Mark. Apparently he had taken his medication that day and had been drinking and wasn't feeling like himself. (worst excuse) I asked when it was and learned that I was actually home in bed at the time, it happened in the living room and I didn't get the full details. I felt really weird about it, being in a committed relationship, I myself am straight and my boyfriend had mentioned being bi-sexual before but because we were together I just forgot about it. I was disgusted and didn't know what to do, I felt most betrayed because this was someone who I hated, didn't want to be a part of our lives to begin with, and now I couldn't trust them together in a house that I couldn't afford without one of them there. I chose to kick Mark out and threatened him to leave us alone. I considered that maybe it was something sexual that I didn't understand, and my boyfriend was very honest about it. I told him I found it odd but would try to forgive and trust him. I wasn't willing to lose everything we had together and he said it was a mistake that he made. I tried to cope but I soon became very paranoid, depressed, anxious. I had come from a very dark place years ago and I felt that I was headed back there. I soon started calling into work, staying in bed drinking, I shut down. I felt let down that after everything a stupid hook up would cause all this drama. I told him he could have the spare room until I decided what to do, he continued to sleep in my bed a few nights a week because we both felt alone. Mark persistently called and text messaged him stating that he thought they had some kind of romantic relationship going on, where my boyfriend told him no, and that he made a mistake and didn't want to lose me, so they should cut off contact. He continued to message him, and I continued to try to understand and forgive him for it, and realised that I couldn't, so we decided we would be friends, and we are. We are closer than ever although we don't discuss what happened because he comes from a religious background and people seem judgemental about same sex relationships/etc sometimes. Today I have been with my current boyfriend for about 5 months, we are doing well. I Met with my former boyfriend this week who told me he was seeing someone, and wanted us to meet. I agreed and thought we could do something. She didn't look at me the entire hour car drive from where I live, didn't say one word. I made efforts to get her to speak up and had no luck. I went home confused. They later came to me and apologised saying that something had happened with her friend over the phone and she didn't mean to be rude, i gave her a chance again and we all had some drinks at my house. I later realised that I had met this girl before. I didn't see us being friends because we were so different, but I also remembered that she was trans-gendered. I have no problem/opinion on this, except that I took it very personally that my Ex was with her. It made me feel like my self worth didn't exist. That he was always confused about his sexuality and used me as a way to avoid it or to create an image for himself that nothing was going on. I feel betrayed, and like I never knew him at all in all that time. I did a lot for him, I changed a lot for him. I became someone I never thought I had the capability to be to make his family happy and to built up myself, just to feel now that it was all a hoax. I don't doubt that he meant it when he said he loved me, but why is he suddenly doing all this stuff that he never mentioned before? Should I just but out and stop caring? I feel so uneasy that I don't understand the sexual parts. a person is a person and their personality should determine whether or not you have chemistry. I just don't get it. We were talking about having kids together, building a life. and it all got screwed up

When you wrote this... did you find clarity? Read it as if you were reading something someone else wrote.... it has to be clear to you. You know the answer Youre just not sticking to it because you keep getting lost in the details, the experiences, the memories, that you have had etc.