Jenna Some tough love may be in order. First I want to touch on what the therapist said about you being a tad bit overbearing. This little detail seemed to be glossed over when you mention it.
Additionally I've noticed you have a huge preoccupation with the "so called OW". I say it this way because based on what you told us there was never anything going on, and if anything your BF probably struck out. IMHO the problem is not a fear that their relationship will suddenly spark into a full on affair. It's your own anger at J and feelings of inadequacy about him going for another woman that wasn't you. You are not worried about her, you are angry at him, and it shows in almost every post you write.
If you keep hounding him about it, he will leave again.
Look the vast majority of people here understand your pain, and we are happy and proud of you. I think you should step back and see if you are treating J like a man. This includes if you make him feel like a man.
I know I'm cherry picking from your posts, but you mentioned J is a push over, your therapist said you are very interrupting, and you wish J would man up. Could there be a chance that he is somehow intimidated by you?
I mention this since I see a chance of this being a feedback mechanism where J is intimidated so becomes a push over, only to irritate you about it, which makes you more angry, and him more compliant.
Eventually he either gets tired of it and leaves or cheats, or you get tired of him and leave yourself.
Bottomline I don't know how the dynamics work between you two, but some stuff kinda stuck out to me. Take some time to analyze how you treat each other and see if you two fall into unproductive patterns of dysfunction.
