Too much spicy food....
There are lots of possibilities, but it means something has changed - the question is - would that be something in him or in you?
That may be true, but it doesn't mean that in your mind you are completely where you want your relationship to be, so it might be playing tricks with you!
I hope you can see there might be a crack at the moment and what might be causing it?
You are watching shows that feature people cheating perhaps?