One confused gay guy

I'm a gold-star gay and have been really lucky to have found a great guy. We've been together in a monogamous relationship for the last 5 years and counting. Recently (or may be not so recently) I've been slowly realizing that I might also be sexually attracted to girls.Deep down I know that I prefer guys and I love my bf with all my heart. However.... I can't help but regret that I didn't experiment more when I was younger. I dated and made-out with girls when I was in highschool but not much beyond that.My bf has had some personal insecurities which have manifested in him having trust issues with me hanging out with other gay guys. Over the past year, we have made much progress in this area and he finally feels comfortable with me making friends with gay guys (even via grindr). I'm scared that if I told him any of this that it would just make him worried, and the last thing I want to do is hurt him in any way.I know that sexuality is this fluid thing, so I hope that there might be others out there that have gone through similar feelings. If so, was this just a phase for you? Do you still have regrets or have you come to terms with it never happening?