Sexual orientation feels messed up and in a relationship

Hey guys, I have a massive problem right now, I've had a boyfriend for almost 3 years, with a break for a few months in the middle. I feel like I'm having phases, going from one sexuality to the other, I've loved my boyfriend so much, and I still do, but lately, especially yesterday, I'm not feeling attracted to him, i feel like im becoming more attracted to girls. I didn't even feel that much into sex with him unlike normally when I see him, where I'm usually all over him while we're trying to watch a film. My mate at work who is my age has am extremely attractive girlfriend and sometimes I just think I'd like a girl who was that fit than have a bf, it's not like those thoughts are me, I never used to think like that, at the start of this year, I just wanted a slim twink, now though, I feel like that has changed. And I don't know what to do, this wouldn't be so bad if I wasn't in a relationship, but unfortunately (or not) I am, which means if my sexual identification changes then it will really hurt my bf.

 

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