I had a friend who had and was 100% responsible for their children and then had to deal with a sick partner. This person after all of that wanted out of the relationship because they were tired of holding up their burden of maintaining it all.
They were exhausted and wanted to be free. Did this person devolve? IMO, no they realized they had nothing left to give or even to give to themselves.
The thankful part you found out was he had nothing left to give, so he was being real (even if his dreams and fantasies weren’t your desires) in saying please don’t waste any of your energy and time on me as life is short.
Not every relationship is meant to be and quite a few have an expiration date. The key thing is after you heal and spend good quality time finding what are your core needs and desires, then you can rank what is important to you in your partner.
He did state what bothered him, and it sounds like a lot of the constraints of the patriarchy and he doesn’t want commitment or to manage a relationship. It is good things are ending then, since someone who wants to spend $0 is not worth investing time and energy in.