My bestie left me few months back because his girlfriend became insecure and told him to leave me. Now he is back to me(still in a relationship with her). He says he feels guilty that he was rude to me and says it won't happen again. He says his girlfriend shouldn't have separated us. And that he doesn't care if she leaves him. He is being really nice and helpful to me nowadays. And shares his life with me( which he never did before). My ex thinks that he(my bestie) is because I have groomed myself completely.. my ex and bestie hates each other.. I don't know why.. though they have never talked to each other. What should I do? Is he really guilty of what.happened? Or is my ex right?

Do you like playing second fiddle to someone else all the time... if you stick around for more than a casual friendship... you can expect a lot more of the same.

It sounds like a lot of your relationships are surrounded by jealousy, insecurity, and mistrust. I would think this is due to the younger ages involved. At any rate, you would do well to figure out what a true friend is, and make sure you put your priorities to finding those characteristics you value in other persons. I'm not a fan of friends ditching me until their minds are made up that they made a mistake, but to each their own. What happens when your bestie finds another girlfriend?