I'm confused

Okay so I've posted anonymously just because I fear judgment on the situation. I'm having a really hard time figuring out who I am. I have always identified as bisexual and have never struggled with the matter. I'm currently 18 and I'm in a relationship with a guy who has not long moved in with me, however I'm really confused about my sexuality. I love my boyfriend so much, he's really good to me but I just feel like its not the right love, at the same time I don't want to make a rash decision and break up with him especially after everything he has done for me he's helped me clear up some minor debts and furnish the flat some more and also lent me money in times of struggle. the biggest thing is that he has just moved in to my home, even after I advised that we wait, and now we are beginning to bicker and argue and I'm seeing all these things that I don't like. In general guys don't really attract me or interest me but I do enjoy the company of my boyfriend. I'm definitely finding it hard though because I feel in myself that something isn't right but I just don't know how to approach the situation. I think I'm a lesbian but I honestly don't know what to do or think, it's a question that has been troubling me for around 2 years now. Do you guys think I'm just in complete denial or am I just being plain stupid? Someone give me some advise please because my head is going to explode.