Stuck between a hard place and the biggest rock.

[MrBond]

"It'll be too difficult to explain here all the subtleties of the how things changed, but they have for real."

No I think you've articulated very well what you've been doing. In fact, you've been going overboard in some instances to show us "hey look how I've changed! I'm a good boy now! Now she has to come back."

"I knew none of this the first time. If I'm given a second chance, I won't blow it."

That remains to be seen. If you don't change your ATTITUDE instead of just your actions, you will be here in the same position.