I want you to know when he sees you moving forward he may find himself questioning his decision. I want you to prepare yourself for this. I'm not saying you need to make any type of decision, just simply prepare. Run some scenarios through your head. Prepare your responses.
If I remember correctly, when he returned previously, it was because you began to move forward with your life. I expect the same to happen again. He has feelings for you, he knows he has done wrong. His confusion will falter and his true intent will prevail, let's see what it is.
