Confused..I trust him but why is he doing this..

Soo.. about a week ago it started hes in the room with me at night and as soon as I sleep I'm a LIGHT sleeper... he goes outside in the living room and wont come back in for soo many hours like 3 4 5hours later...

I asked him why is he sleepin in the living room he said it's hot in the room ummm okay... is this a excuse?? Would he be upto something should I ask him I do trust him but seems fishyy... if it hot u can turn on the fan or turn off the heater

What would u do or assume ur SO is upto if he did this... he was fine a week ago why has he been doing this everyday

...currently hes in the living room on his phone.