You'll get to the point where you can have the convo, I don't blame you for not wanting to get into it at the office either.
Perhaps when you do have the convo, because of her rant, you could approach it as "honey I know you need to do something for yourself, I understand that...but right now I see you adding to your stress by not limiting the number of dogs/cats you take in, it has gotten out of control."
At least that way you don't discount that she needs something for "her", but you are also pointing out...there has to be a limit. This could lead in to you letting her know too because she doesn't limit her time spent w/the rescue that she leaves no time for you two as a couple.
