There is no reason to feel pity for someone who refuses to help him or herself.
I do not think there is a need for an ultimatum here. If your wife is willing to deal the relationship, then she should not complain about it.
If she’s going to complain about it, then she needs to end the relationship. It’s very tiring to hear someone complain about something if they’re not willing to change it.
I think you just need to help your wife see the situation as it is and remind her that she and Cher are no longer children. Cher only takes. A true friend also gives.