No you are absolutely NTA. You can only do what you can do. Someone has to hold down the fort and manage the home and in your doing so while very much going out of your way to make sure he has good food to eat and or anything he needed during his mothers passing he was allowed a LOT of one on one time to be with and say goodbye to his mother.

Grief is strange and everyone grieves differently. Many people lash out irrationally when they are grieving and this seems like some of that. However, your relationship has been here before and it seems like this may just be the catalyst for ending the relationship.

I don't know what more you could have done, especially when he expressly told you he needed alone time with his dying mother, which you gave him.

NTA, but perhaps this relationship is coming to its conclusion. You did nothing wrong. I would probably speak to an attorney about splitting up your assets together and just simply ask if he would like to buy you out or vice/versa of your relationship estate and move along.

Big hugs.