So i was involved with a clinically bipolar guy since early last year. He was nice initially. I saw a few red flags like us not having any pictures together and him not introducing me to his family but I ignored them because I thought he would have changed. He moved early this year. He didn't say bye before leaving, only through a text message and became a bit distance the month before he left. Early this year we would speak here and there but not often then he comes home to visit in May and wants to see me, we hook up and it was good then the following day he is with another girl spending an entire vacation with her. He never does those stuff with me. So i called him out on his behavior and stood up for myself especially because I know he's not taking his medication for bipolar so I told him that he should because his behavior isn't normal. He apologized and I guess we moved past it. After that I was in the process of trying to move on from him. I didn't contact him and he didn't contact me. A few months passed and I felt like I was ready to check up on him just to see how he was. He told me he was fine and asked how i was etc. It was a typical common courtesy conversation. I later on saw in the day that he was at a theme park with a girl that he went out with last year while speaking with me but it didn't bother me because I was trying to move on as well. A few hours later after the conversation ended he messaged me again surprisingly and asked what am i up to and i responded and said i'm relaxing and asked how was the theme park. He then responded and said that he and I are not in anything and that we hardly speak and asked what my problem was. I was shocked because I was genuinely asking how the theme park was. How should I treat this situation and what are your thoughts on it?