How do I respond when I'm tired of hearing it?

Sounds like they are equals and found their shared bottom (to sink to) together. Don't take him down, she'll end up defending him and sticking with him. Just tell her "Well, at least he works and doesn't spend his money on drinking." Or "You don't have to stay married" helped my mom the most, for me it was "If he is going to be here I need to leave." Just don't say anything accusatory just neutral and honest.