I recently went through this myself. I was with a guy for a couple months. Long story short, he did something wrong, then came back and apologized and said he only wanted to be with me, we had a great talk, a great few phone calls after that, hung out and had a great date, then he disappeared and never called me again.
Sometimes, when a guy has been unsuccessful in his attempts to get his ex woman back, he might begin to think, “Maybe if I just stop chasing her, she will come back to me by herself. The time apart will make her miss me and she will realize that breaking up was a mistake.”