Feeling lost

Hi, I'm new to this forum. I just feel I need to talk to someone who understands what I'm going through. My daughter is 38 and has never been diagnosed with a mental disorder other than PND, anxiety and depression. When she had her first baby 17 years ago she suffered from PND and on several occasions tried to commit suicide. She has been with her partner for 20 years but recently left him because of domestic violence. Sometimes it could have been from her anger towards him, however there is no excuse for what he did to her, I was in constant fear he would do to her. After getting a restraining order and leaving, him the children decided they want to live with their father and have no contact with my daughter anymore. This has caused a decline in her mental health. She met another man and moved in with him way to quickly as she couldn't afford her rental anymore, as the children aren't living with her and she only works a few hours a week, as that's all she can deal with. She says she loves the new guy but she has driven him away by her unpredictable moods, screaming, throwing things and threatening him with a weapon. She is so convinced that he doesn't love her and will leave her, all alone, that now she has driven him away. He wants to break up with her but she is living in his rental ,with him, and he doesn't know what to do. We have been through 20 years of this and my husband and I are both on antidepressants and I'm in therapy trying to get through. I can't have her move in with us because I feel that will be the end for me. I can't handle her screaming and I'm a little bit scared of her too. She has turned to alcohol as well which really makes her unpredictable. She has also had issues with drug abuse in the past as well although she hasn't used anything for about a year. Do I let her move in with us or is there any other option? I can't bear the thought of living with her but I equally can't bear the thought of her living on the street.