Things change and there isn't anything wrong with exploring relationships and your sexuality. 16 is such a confusing time and suppressing those thoughts and feelings won't do anything to benefit you.

Personally, I think if you are mature enough to engage in having sex, then you need to be able to openly talk about the status of your friendship. He obviously feels the same way physically from what you describe. I would tell him that you both need to have an honest discussion about where you stand right now. If one of you wants something the other does not, that can very quickly turn into jealousy and resentment. Especially if they end up dating someone else.

I have been in this situation before. This guy had a huge crush on me for a few years but I was dating someone so we were just friends. I broke up with the guy and had been single for a little while and decided to try it out. We kissed, never slept together. Ended up feeling weird and we are still friends to this day (8 years later). In fact we are texting right now about fantasy football haha

My situation worked out well but that doesn't always happen. Open communication is needed for friendships and relationships. This should be good practice for both of you no matter the result.