Is it a mental illness?

I am 24 years old male and right from the time when I was 15 years old, I used to fall in love with anyone who treats me right, I've fallen for my close friends, relatives, colleagues, even with my teachers. And every time I felt that, I knew I had to kill these feeling so I always separated myself from the person.

Now, the problem is that now when I fall in love, right from the time I feel for someone, I feel intense heart break, I don't know if I've trust issues or what, but this way I can't move forward in life.

Is it because I was ab*sed in my childhood? Or what? I never came to know.