I think it's normal to be cautious, that's your gut feeling, you should go with it.
When someone who has been our SO "turns" on us (and I know that term is a bit strong) it can be really unsettling. In my first divorce, which was a very amiable divorce generally and quite fair, my exh said he would pay off our joint credit card when all was settled with the house. He then decided not to. In that case I don't think that was particularly unfair or anything, just an example of how feelings about what is fair/feelings of generosity can change.
Keep in close contact with your lawyer as this will certainly make you feel that all is in order and on track.
Hope the reno day is less stressful than you anticipate once you get started.