I have been talking about this with my counselor, V, do you have one? Sorry I haven't read your whole thread.
In my case I haven't slept with anyone else but I have been on a few dates. (Granted we are D'd as of Feb.) Anyway lately as soon as someone I am chatting with via Match wants to go on a date, I get nervous and pull back. I realize that I am really wanting to be going on dates, kissing, touching my ex. Don't know what that says about us but just know you are not alone!
I do have to remind myself, no matter how much I may want that from my ex, it is not an option. Not now, maybe not ever.