Am i a lesbian or bisexual?

Ever since I was young (middle school) ive been attracted to girls. Whenever i masturbate i can only think of and look at girls to get turned on. I can only find men sexually appealing if I have romantic feelings towards them as well. I do find guys nice to look at as well but I just think women are better. I also have thought of dating women but I've never gotten a chance. So what sexuality am I? Also I never tell men that Im in a relationship with that I find women attractive because most men see this as sexy and I do not want my sexuality to be objectified. Also I'm the jealous type so I don't want my boyfriend thinking it's okay to check out women in front of me or look at women with me because I have tried that in a relationship before and I felt very uncomfortable. Do you think it's wrong of me to hide my sexual preferences from my boyfriend? I don't want my boyfriend to get turned on by it or ask me to have a threesome. That would make me very uncomfortable. He's also homophobic but I'm sure like any stupid homophobic man he thinks being a lesbian is OK while on the other hand it's "disgusting" to be a gay man. We rarely discuss gay rights or being gay in general but I make sure to tell him that I think it's disgusting of him to be prejudice towards gay people and I make sure to let him know my thoughts about the matter. He has said when I told him that he has no idea how hard it is to be gay, "How would you know? Aren't you straight? Are you gay?" I didn't know what to say so I just said "No but many of my closest friends are and I'd never wish the types of things they've endured on anyone." I've also never came out to my mom because she doesn't believe in bisexuality although she does support gay rights (stupid I know). But then again I don't even know if I'm bisexual or not. I'm 19 BTW.

& Sorry for rambling but could someone please answer my questions and give me some guidance. I feel very confused.