Confusion

I don't know if any of you have ever gone through this, but what do you do when a fwb/nsa (yes, it can happen) becomes something attached? That's the best that I can explain it.

I'm an honest person. So I told S. about seeing Ryan about a month ago. S. got all jealous but of course said he wasn't jealous but it was noticeable. He just said he was upset. As you all know, s. and my schedule hasn't agreed since the first of August and here it is October. Wouldn't you be happy if your fwb/nsa-person saw someone else when you couldn't be with them?

I'm just worried that he's developing feelings. I've done my best not to as sometimes I typically do (you know how it goes). A friend told me to nicely tell S. that me and him aren't in a situation where he could be my full time boyfriend.

Anyone have any suggestions?