I don't know if I should feel??

I've been with my so for a year and a half well just within the last month I've been hooking up with a girl, we haven't had sex yet but we hang out all the time and we have kissed and almost got crazy to the point we wanted to rip each other's clothes off but we want to wait, she's 40 and I'm 21 and the way she makes me feel is indescribable, she makes me so happy and i feel alive when I'm with her. Should I feel guilty about this!!??? Or will this pass, my boyfriend knows we hang out all the time but doesn't know we kiss.