I am going to respond in a slightly different way, and I hope it helps.
First, whatever motivation/reasons you have to pull out all the stops and get that last 18#s off, I am pullin' for ya, girl. Nothing wrong with making your ex. see what he's been missing out on, either. I love it.
Sometimes pressure backfires, so as far as that aspect of your post goes, you may find it helpful to use some Beck Diet Solutions techniques. Dr. Beck advises that you write your reasons for wanting to lose weight down(she calls them Advantage Response Cards) and review them several times per day. There is a whole Beck Diet Solution thread on 3FC..please feel free to check us out there if you like.
The other advice I have, and I am going to take my own on this one, because Lord knows, the final 10#s are the hardest, is, for what it's worth...I bought a book called Flip the Switch: Proven Strategies to Fuel Your Metabolism and Burn Fat 24 Hours a Day. I have read it all; some of it makes sense to me, and some doesn't, but nothing that the author suggests really could hurt much. He does make some claims about not needing to exercise so much, and other things that seem a bit over the top, but some of the tips seem to me to make sense.
Fidget..keep moving, don't sit at your desk for more than 15 minutes without moving. Sip ice-water throughout the day. Chew gum (sugarless of course)..get moving first thing upon awakening..he has suggestions for 10 minutes of getting yourself revved up in the morning..get as much as light as you can the first thing in the a.m. ..kinda a metabolic wakeup call..as I said, some of it makes sense, most of it couldn't hurt to try.
Good luck. I look forward to hearing of your progress.
P.S. thanks for making me look up "acrimonious".