Why not let him know this week does not suit you. Maybe do so by text so you are not obliged to reply for next week. These interactions are weighing on you. Understandably so. You wonder if you are on the brink of a turnaround.

If you are putting off your meeting won't change that. He will come back for another time. I think you should take a little time to settle your thoughts.Plus it'll do no harm to not be available. May even help him review things.

Your daughter has not walked your shoes. It is more difficult than she could imagine. Don't beat yourself up but it is good to realise you are not as positive as you could be. What steps can you take to improve that?

Best wishes

R 25 years
M 14 years
S11 & S13
Working on it alone since Oct 2014
M in trouble a lot earlier (~2 years)
Feb 2016. 1st R chat in a yr.
Next R chat Aug'17
Still together