In love with him.

I'm going to make a long story short. My ex and I stopped seeing each other because he decided to give his ex another chance and she now lives with him. We went a year with no physical contact and very minimum contact via text for a year because of his decision. However as you can probably guest where I am going. He is back. It seems we just can't leave each other alone. I tell him to stay away because she is still there and in the picture. But he won't stop and no matter how hard I fight with myself I can't deny him. I know I sound very crazy and extremely selfish and stupid. But I can't fight it. Have you ever felt this way? How do I stop this? .... And please don't hit me with that home wrecker side chick b.s.. It takes two to place the game.