There is no reason at all for the boyfriend to be there. It's nervy that Daughter probably guilted you into housing him. He should go, even If daughter throws a toddler fit. And he can take his pets with him.
Your daughter is not even acting appreciative of your sacrifice. What's with that? Drugs? I take it their lives are a mess or they would prefer, as adults, to live on their own. Mature adults don't want to live with Mom. Or take her money.
Remember this: Your life is as positive or as negative as YOU make it. We write our own stories and some chapters in our life book are uncomfortable and hard. But it is in your hands only. The boyfriend and pets end even abusive daughter can not live with you and make your life hell unless you allow it.
Maybe private therapy can give you insight into why you feel the need to invite this into your home, which should be your sanctuary. Do they pay bills? Clean? Mow the grass? Act respectful? Offer rent? Work full time? If not, why even CONSIDER letting them in your house, especially this likely bad news boyfriend.
But your daughter is acting undeserving too. I know you love her...we all love them so...but how does it help her learn to grow up if you take her in with no expectations and even allow the boyfriend to mooch too??? I am sure she bawled and tantrumed and threatened you and guilted you to get you to do it. They all do this. But many of us have learned that the lying manipulations are all baloney...and we change our decisions.
This is your house. Your house/your expectations in order for anyone to live with you/your rules, not theirs.
It sounds like a crazy life right now. Please do learn to be nice to yourself. Therapy, therapy, therapy! A pastor if that is easier. And understanding, WISE good friend. Somebody who is in a better place than you are right now please.
You can't live forever. Then what? Daughter will be lost.
I do hope you can learn to stand up to them soon!
Wishing you love, light and peace. You can do this. Many of us have. It's never easy but it gets easier with time.