Why do I have bad luck with women ?

So I was in a relationship with someone for 5 years and we broke up almost two years ago. Couple months after the breakup we was still going on dates and having sex. So last March when I tried to get everything back to how it was she didn’t want anything to do with me anymore because it was too late. So months later me and this girl got very close we was already close friends like brothers and sisters then her and her fiancé broke up so it became a advice thing then a physical thing then a emotional thing. So long story short she went back to her ex fiancé. During the months I started dating other girls and it just didn’t work out I wasn’t interested in them like that. So the girl that was engaged contacted me and told me she miss me and she’s sorry for going back to her fiancé so I gave her another chance because I actually like her and it lasted for two weeks and she went back to the fiancé. Two months later I met this girl and we have a lot in common. We like basketball and everything so I thought this could be it. We went on our first date and it was wonderful she was smiling and having a good time. Everyday we spending time with each other so one night I had left because I had to do something for my brother so she was upset about that. We made up for it the following morning and we was back to normal. A few days later she said we should take a step back because she get irritated too often. Why everytime I like someone I get the short end of the stick.