Cat Pooping Problem

My companion and I have been best buds for 6 years this upcoming Labor Day. We've been thru a lot, 3 years of college, 2 apartments, 3 houses, a hand full of different roommates, friends and a baby. We currently live in a home that I've purchased, 3yrs, and are in it for the long haul. My gf and daughter have also been here since the beginning.

I would also like to add that he is a strictly indoor cat. There was a short period of time where he was outdoors when I lived in the country and nothing was around us.

Since the beginning we've had some issues that frankly are getting a bit out of hand. He continuously poops outside of his box wherever he wants. I've done pretty well keeping up his box, I admit there were times in College where I found activities that were more important to me then. He's received so much love over the years from everyone that's been involved in his life. I've taken him to the vet on separate occasions besides his yearly check up to discuss the problem with different vets and assistants.

We've tried: multiple boxes Different litters (scented, unscented) Multiple boxes with different litters Moved his box - in the house he essentially has his own room Put his face in his mistakes

Even when he was allowed outside, the basement area still had poop. I would consider letting him out again, but we live on a busy street.

The vets don't know what the problem is since we've messed around with the variables.

It's as if he does good then All of sudden there's poop at my door. The last week or so have been everyday. It's really getting on our nerves. We all love him and our daughter thinks he's the greatest thing in the world.

I'm looking for any advice.

Thank You