"We made it a couple more months but ended it a month ago because it is extremely exhausting".

Right there tells me a lot. A positive relationship isn't one that exhausts you. He is getting under your skin and sucking you dry sweetie. He is using you. Once you are all used up, you are gone.

He only seems like he was a nice guy now that you are not with him. You deserve much more. When you are with people you care about and they care about you, it addes to you not takes away.