Why does my ex come back when he says he wanted to date someone more popular and successful?

About me: I'm 29 I have my own apartment in the city and working in marketing. I've travelled solo all around the world when I was a student.

I was seeing this guy who is also 29 for a few years long distance and even asked me to live with him. But he seemed so difficult to please and always had something to complain about me about my appearance. I'm in shape look after myself and was a form track and field athlete. But he would dump me off everytime a girl would give him attention
Why does my ex come back when he says he wanted to date someone more popular and successful?
Post Opinion