I’m 24F dating a 30M

I’m in a 6 year relationship, I bought a house this year under my name and we go half on our mortgage. We split 50/50 on everything so he’s pretty much my roommate. I’m a gym girl and recently my gym crush hit me up. I feel horrible for responding to him but I couldn’t help it, we have been texting for awhile now and I have gained feelings for him. I really don’t feel the same for the guy I’m currently with right now. How can I get myself out of this situation?? I’m crushing hard on my gym crush but feel so bad for my current bf