Masturbating?

I usually am a fairly horny person and would masturbate quite a bit, but a few months ago i got on birth control and also recently got my first boyfriend. Im easily turned on when with him and we haven't had sex but he's made me cum many times, but now I just don't ever feel the urge to masturbate and its making me sad :( I don't even see my bf that often, maybe a few times a month. Do you think it's my birth control?