Help!!!

So my friend has been talking about her new boyfriend and how happy she is with him. She was telling me how she can't wait for me to meet him. After she showed me a picture I realized that he was the same guy that I've been hooking up with on a regular basis😬😬😬😬 I really like this guy too so I don't want to have to give him up but now it's weird. I know I should tell her but I started hooking up with him first. It's just super awkward!!☹️☹️🙁