Hi Anna

I think you need to treat the situation as though it is a break up. It sounds very much like you have been very supportive of your partner over the course of your relationship. Depression is tough to live with for  partners as much as sufferers. Its time to put yourself first and deal with this in a way to strengthen your resolve and so he can understand you are not to be dragged into his emotional yoyo-ing. Set him free, set yourself free, live your life for yourself and IF at any stage he regrets his decision, he will need to work to regain your trust.

BB