Pattinson had briefly separated from Stewart, 22, after her affair with married director Rupert Sanders became public. After a much hyped break-up Pattinson reportedly decided to give the actress another chance because he really loves her.
"He really loves her and is scared (of) what others might do to him in a relationship. He thinks that they might use him or have different intentions.
"He is comfortable with Kristen, and he is happy with her, and she knows it. He feels that she is the best for him," a source said.
The couple met on the sets of movie "Twilight" and have been together ever since.