Ending the A as of now is definitely the right thing to do, but I have to caution you about one thing:
The one and only way to ensure an A does not start up again is to cut off all contact with that person - no calls, no email, no letters, no text messaging, no instant messaging, and absolutely no physical proximity. You have to be committed to doing this as much as possible (some times it's impractical) if you want to avoid temptation, both yours and his. I'm not trying to harp on you, I'm just trying to give you some advice based on the experience of others.
