Depression

have any of you had a partner with severe depression? I've never had one before, but my present partner of almost 2 years has severe depression. Some days are better than others, but when it's bad, it's terrible. He pushes me away and when his depression is in full swing, he treats me like garbage. It's usually only for a day or two and his depression goes away.. he apologizes tells me he cares, and it's fixed.. I know depression is a serious thing and I can't punish him for his mental state, but sometimes enough is enough.. I have so much love for him, but I don't know what to do sometimes.. I need some advice 😔