Anal BF

I'm 17 but the list didn't show that. I am female I have a boyfriend, he's my second to have sex with and the first guy was only three time, and two times with my hand. He dumped me for a cheerleader. My boyfriend now is great, we've been having sex for a year including my using my mouth on him (didn't use mouth on the first guy, he didn't stick around long enough), and something I really really enjoy, him using his mouth on me. A week ago against my better judgement and his constantly asking, begging pleading, and sometimes demanding; I let him have anal sex with me. I've not had it before and it was hurtful, and quite frankly even though it hurt physically I put up with it. I really felt terrible about myself that I actually did that. It's so dirty back there, I can't understand why he wanted to do that. Now it's almost all he wants. In the 9 days since, we've had sex 7 times, 5 of them were anal and only two were regular. I want to please him and don't want to have another guy dump me but it's really messing with me. I don't go to the bathroom the same after and not for the past week. Plus I really feel that I'm now like a slut that I let a guy do that to me. I'd be so embarrassed if he told anyone. He swears he won't tell anyone I let him do that. I want to do it for him and I will, but I want regular sex that I can get something out of too. Not all the time anal.