Dom "I don’t want to" + "I'm not in the mood" IS NOT EQUAL TO "I cant".

I agree with that process and thought.

People like that who say "I cant", are simply using it as a verbal shield to hide behind, rather than being honest by saying, "I don’t believe that the benefits to me of doing it, are bigger than the negative impacts to me of not doing it".
That is the whole truth in many cases when someone says they can't.

I see the connection Dom, between I can't or as I put it A+B=C, as the person isn't motivated.

I still have a situation, like many, of wanting what my SO doesn't value very highly.

What I see is a SO will do somethings, sometimes, and to a degree. Sometimes that action can be a gift and appreciated as a gift. Sometimes it is offered but not happily or freely given.

Lou