Well, you tell her you love her... so she knows that...
I don't know if buying her flowers would be a back slide... it would depend on the difference between her expectations when she moved back in vs. yours...
What I'm trying to understand is what conditions were put in place and who chose the conditions when the two of you started living together, again...
I think what's worth looking at here, over the past four years is how you didn't feel it was necessary or worth continuing to DB...
Not being sarcastic here, but did you expect that maybe she would change her mind?
Why, now that she's pushing D, are you interested in working on DBing, again...?
It is great that you want to, but did you get any sort of indication that she wouldn't simply D you, eventually...?