He prefers his hand over me :(

My boyfriend and I live together and have been dating for a year and a few months. I have a high sex drive and am willing to have sex with him whenever he wants it and he knows that. Well I caught him masturbating in the shower while I was home and willing and it made me feel like I'm not good enough for him or something. It hurt my feelings that he would rather use his hand. I was wondering if that's a normal thing guys do?