Just sticking my nose in....I don't usually post to these but...you sounded sincere and as a girl myself, I thought I should explain...certainly, what I think may/may not apply to the rest of the population...however...
women want to believe they are special. After you first break up, you should give it a break and not screw anyone else right away...out of 'respect'. It is like a loyalty thing. It's like a guy that joins the Marines for four years...hoorah and all that shit...then turns around and joins the Army or something....just seems disloyal...
...in my experience, break-ups tend to be short-lived...so you should wait to make sure you have really broken up so you don't have to deal with the guilt crap later when you get back together.
..but then, you knew this already...you just want some affirmation of your current position...
funny how I've had this same problem when I date men...so it isn't just a woman thang.