Man trouble. Need advice

So after a nice day/night together my fiancé goes for a bath nothing unusual comes out and his personality towards me has changed! I did nothing but watch TV, he didn't have a phone or anything. He then decides that he's sleeping in the spare room 🤔 when I asked why he said "I'm working early, go away" I'm confused and tell him that's not a good excuse. He then said that he's staying in there because I'm in the room 😔 I have no idea what happened so I'm now sitting in the living room typing. Anyone any idea what could be wrong.