Most Helpful Guy
I recently was in a relationship with someone that had a similar issue. The best answer I can give you would be to just work on your own life. Find new goals and hobbies that distract you from thinking you need someone around all the time. If we don't have any time to ourselves then we are not self aware and that is dangerous for our well being. I faced this issue when I was younger but I eventually broke that by heavily occupying myself. There is something about someone who spends time alone to deal with the emotions, comes out confident and happy. My good friend told me when day, if we look to others to feel happy then we will end up being miserable. I hope this helps. It does get easier, I can promise you that.
Most Helpful Girl
Well you probably have a problem being since, since you've had a few relationships. I for example, am happy haha, because I've never experienced being in one. I think what you need to do is learn to be independent from a guy. Take for example one day and do whatever you enjoy or like, like things you're passionate about, shopping, watching movies, tv-shows, singing, anything you find comforting and fun to you. These things could probably make you realize what a great fulfilling day you had and that you were able to be happy without a guy :) Good luck!