I'm really scared of my sexuality

So I'm almost 19, I've only ever been with guys, and I've had a serious boyfriend since I️ was 15. I love him to death, I find him so sexy and I wouldn't wanna be with anyone else. I really enjoy sex with him and I love kissing him and being with him. But for some reason I've found that lesbian porn turns me on if I'm on my own, but I️ would never want to kiss or be in a relationship with a girl. I️ only like kissing and being in relationships with boys, but I'm really scared and don't know why I'm turned on by watching that?? I️ don't want to be lesbian and I️ don't want to be bi. I️ have absolutely nothing against people who are, but personally it's not the life I want so I'm really scared as to why this happens to me. I actually don't find any of my friends/girls I see every day attractive in real life, it just seems to be the ones in porn. Is something wrong with me?? 😰😰