Family issues, husband issues

My mother is mentally ill and becoming worse. We can no longer let her around the baby unsupervised and I'm dealing with a lot of anger and sadness over her narcissism. My aunt has brain cancer after battling and beating breast cancer. I lost my job but have been so very happy taking care of my daughter who is now three months, she has kept me going through all of this and me and husband have been doing pretty great. Last week I went insane and took us to look at some puppies, we brought one home. This week has been the worst, I've been crying every day bc the puppy turned out to be the tipping point of my anxiety. Our old dogs don't like her and neither does my pet pig, she's annoying all of us and she's *playfully* bit the baby a few times which made me yell which made the baby cry, also the barking. I can tell baby is affected bc she's cried more this week than ever. I've been begging my husband to take her back (we took her on trial basis) but he's refusing, he "loves" her so much already and is blaming me for taking us to see them in the first place. I'm on the edge of depression and I don't know what to do. His mother said I can come live w them until he takes the dog back but that sounds shitty, we should be able to make his decision together. How can I get him to realize that the pup has to go? That my and our babies well being hangs in the balance and the dog is not worth it?