boyfriend and girlfriend

One day, boyfriend go see doctor he said, doctor, i have two problems. the doctor asked what kind of problem? he said, when i visit my girlfriend. First, I sat next to her I feel so cold when i went second time I feel so hot. Doctor said I don't understand young man tomorrow you bring your girlfriend with you. I will ask her couple of questions. Next day, he take his girlfriend with him. Doctor asked the girl, what did you do? He said when I visit my girlfriend i have those problems. She said, Doctor, you don't understand, when he came to see me first , he said he was cold because its the month of January and when he came to see me second time, he said he was so hot because its a month of July and in my apartment , there's no airconditioned and heater.