Masturbating

Hallie
So last night I was feeling really horny and I asked my boyfriend if he wanted to have sex. He told me no, so knowing that I wasn't going to get anything from him I decided to "have fun" with my hand, me, myself, and I..However, it was right next to him since we sleep on the same bed. 
Thinking he'd find it funny I told him today and now he's mad at me for doing it. Does he have a right to be mad even though he told me no?