When DH and I were planning our wedding (the second for both of us) I told him that I couldn't promise the full vows. In the end we did basic registry (love, honour and respect) then a fully DIY wedding for family where we wrote the vows we were willing to make.
This isn't a TAAT but that did make me think about this.
Basically I wasn't willing to be married to someone who was acting in a depressed manner but who refused to see a doctor, wasn't willing to be married to someone blasé about supporting his family and so forth.
(For the record, we've been married three years and I've supported us through him having a breakdown and him being fired for his attitude which turned out to be Graves Disease).