Is it normal to want to be with a woman when you're dating a guy?

I'm a bi male who is in a similar situation as you. I'm with a wonderful amazing girl who I know I'm going to have a future with. Sometimes though I want to be with a guy for reasons from sexual to social, but at the end of they day I'm so happy in my relationship that I could never possibly do anything to ruin it. The feelings will come and go from time to time, so just roll with it an do whatever will make you happiest in the long run.