Nudes

My boyfriend and I, we been together for 5 months and today he's been acting like a total jerk calling me a slut and what not. Later today we were talking on the phone and asked me for a nude but I don't want to send him one because I'm not comfortable sending nudes. So, he got mad because I didn't send him one. He totally reminded me of one of my ex boyfriends who I broke up with because I didn't send him a nude and didn't talk talk to me for 3 days because of it. But I really love my boyfriend and I wouldn't break up with him because of this. But I wouldn't break up with him because of this. Why do guys get so fucking mad when I don't send them nudes!!