I'd say that you've learned a valuable lesson to just say "No" in future. Meanwhile ... a bite at a time.
I am sort of in the same boat, but my project is my own ... I'm hand quilting a king sized quilt that I started nearly 15 years ago (my first quilt, made strictly for practice and to learn from my mistakes, of which there are many); my DH, who is in very fragile health, loves this quilt and has made it his own and I have to finish it. I'm o.k. with working on it a bit each day until I get a notion to start something new; then I resent the "practice quilt" so much! I set goals for how much of the hand quilting I'll do on it before I set it aside for a while to work on something else, knowing DH will say, "Why aren't you working on mine?" No pressure there!