Is it considered child abandonment?

What is the name of your state? Ohio

My husband and I are going to separate. I was going to move out and leave the kids with him because finacally it makes more sence. I can't afford the house on my own and if I go I can't afford to take the kids with me. I also plan to see the kids daily. If I do this could he say at any point that I abandoned the kids?

It would be very foolish of you to move out without at least a temporary custody order. While it may not technically be abandonment, he will not have to allow you into the home to spend time with them and will easily be able to argue that he is as fit as you are for custody - and your action of leaving the kids with him will prove it.

I'm no lawyer, but I know from experience that if you plan to separate, and it's agreeable between you two, you better get a lawyer involved to work out custody arrangements, visitation, etc. as part of the separation agreement. And make sure he signs off on it too, ASAP, preferably before you move out. Otherwise, all you gotta do is tick him off ONCE and he has all the ammo he needs to say you left the kids. Listen to the voice of experience.