Ex-boyfriend wants ‘custody’ of MY dogs

So one of my friends was giving away two of her dachshund puppies. They weren’t getting along with her older dog and she knows how much I’ve wanted a puppy. So she reached out to me and I told her yes 100% I would love to take them in. My boyfriend drove us to pick them up. We didn’t pay anything for them.

Right off the bat he insisted that one could be mine and the other be his. I didn’t like this idea because they are so codependent on eachother. If one is getting a bath and the other isn’t in the room, they will freak out. They could never be separated.

Especially now after seeing how he interacts with them there is NO way I would let him keep them.

1. He doesn’t like taking them out to potty or go on walks, but instead yells at them when they don’t 100% make it on the puppy pad.

2. He goes out every weekend all day and night and keeps them locked in their crate and even when he’s home on weekdays, he’d rather play his game than keep an eye on them so he keeps them locked inside.

3. He yells and gets very frustrated at them and one of them always cowers down and pees herself when he walks towards her or tries to pick her up.

He’s made some very insensitive comments as well. One time when they got into something they weren’t supposed to, he was going off on a cussing and yelling rant and I tried to remind them that they’re basically just babies and don’t know any better. And his reply was “yeah and this reminds me of why I don’t want any fucking kids.”

Yet, I’m moving out because I’m tired of his ass and he’s still insisting he should get to keep “at least one.”

I pay for all their vet bills, I paid for their immunizations, I paid for their preventative care, I buy their food 95% of the time, (he’s split the cost with me once and bought a small bag of dog food one time)

He bought their crate and buys puppy pads

I buy most of their treats

I buy all their dog bowls, and blankies to keep in their crate

I pay for all their harnesses, leashes, collars etc.

I also pay for their pet insurance every month.

I’m the one that takes them out, bathes them, and I’m the one that always gets up in the morning at the ass crack of dawn to let them out. He will let them whine all morning if he has to.

I love my babies so much. I’ve had nightmares recently of someone trying to take them away and I’ve woken up crying. This is really affecting me.

My question is, what can I do to prove these dogs are MINE, since there was no payment or anything like that? I have some receipts at the vets office and I can also prove I pay for their pet insurance.

I also have the messages of where my friend was asking me if I wanted the puppies as well.

If I had to take him to court, what would I be able to say or do to prove that he should not have them?

In the future I’m going to get them spayed and microchipped. Would that work?

Sorry for the long read, thanks in advance!