I think I've got it figured out

OK, so my cat won't stop pooping on the floor at night and I think I know why. I've been reading up on whats known as "liter box aversion" and one of the reasons this occurs is because a cat has associated bad things to their litter box. I have two cats (one male and one female; the males the one with the problem) and I've notice that alot of the times when my male cat is using the box during the day, my other cat will charge at him after he gets out. Also, yesterday my female was just sitting in the box, my male normally goes in, and not doing anything. She was just lying in there, like she was maybe trying to keep someone out? So the question is, how do I change my other cats behaviour and get my male cat to associate good things to his box again?

You add another litter box (you should have 2 or 3 boxes with 2 cats).

I have three already and I'm gonna add a fourth

Are they all in the same place? I'd try a few different locations and if you have the space try to leave 2 exits so if your girl is lying in ambush your boy can go out the other way and avoid her.

good call, two of the boxes are in the same general area. Theres one in my basement too. I don't think he likes that one because theres a lid on it (keeps the smell in). I'll take the lid off and move the other two and see what he does.

Thanks

Let us know how it goes.

I hope it works for you, but did just want to clarify one thing - the post-pee or poop ambush by another cat is standard behaviour, and not about how many boxes you have.