My ex always took forever in the bathroom, usually 45-60 minutes to crap. You could tell that's what he was doing at first because walking near the vicinity of the bathroom would make your eyes water.

A few years later, it gets longer. 2 hours at times. I don't even care at that point what he's doing, he could be jacking to balloon fetish porn but I have a potty training child, a twelve year old boy that needs to shower for school the next day and dang it I need to pee and we have one bathroom. So I pound on the door and say others need to also use the bathroom. He reacts in a way similar to what you described and finally comes out 20 minutes later.

This happens twice more over the course of a few weeks and I notice the bathroom doesn't smell after. He's just sitting in there.

A month later, find out he's been in there texting and having phone sex with his coworker, who he's been having an affair with for 7 months.

Not saying this is your case, but I would take a good whiff the next 2 hour session he has. I don't know anyone that takes that long to shit or to rub one out.