What keeps you from asking John to leave? I am sure there are good things about your relationship that you aren't writing about here, but the negatives are pretty negative. Being supported by your girlfriend and her husband is a very awkward situation- and not really fair to the two adults paying the bills. You feel used because you *are* being used.

Does he offer any kind of excuse for letting you and your husband pay for him? Or for why he doesn't do anything around the house besides cook dinner? I hope he is the one who cleans up after that, too

Do you think you have a tendency to hang onto relationships well past their expiration date? I know I have done that-- and going through the empty nest phase seems like it would encourage that even more. It's okay to cut our losses and give up on draining relationships. It's painful when we'd really rather fix things, but the reality is we can't always make it work. Letting go makes up more space for new relationships to form.

I am obviously not there and don't really know your relationship, just what I read on the screen, so please take the above with the appropriate grains of salt