We have 3 kids together, unmarried, but we all live together and I wanted to know can I claim 2 of my kids and can my fiance who is their father claim 1 child?

So me and my fiance who is the biological father have 3 kids together, unmarried, but we all live together and I wanted to know can I claim 2 of my kids and he can claim 1 child? Were trying to get the most out of our tax return? Is this ok?