Without talking to you and getting to know you, I can only make some very general guesses:
Sometimes a person both wants a relationship and is terrified of having one. The solution is to have the fantasy of a romance but to pursue men who aren’t really available.
Sometimes it’s important to a woman’s self-esteem to try to get a man to break rules or to get away from someone else. Succeeding certifies that she is special. Of course, it is a false way to build self-esteem and the failures only make her feel worse.
Another possibility is the desire to feel superior as a way to feel “safe”. By choosing men who are immature, married or unable to get a visa, the woman could feel she is more in control.
Or something else. Or some combination.
Bottom line: If you are writing about yourself, I strongly urge you to get into therapy. You already know that you won’t find real love and a long lasting relationship if you keep repeating this pattern. Therapy will help you understand yourself better and perhaps develop the capacity to find genuine, reciprocal love.
I wish you well,