Scared, guilt, ashamed, shy

Montana

So today I had a down to earth talk with my new co worker which is female. It’s that we have mutual feelings about each other. We clicked on today’s break at work and what not. I even admitted I’m attracted to her to this coworker then kissed her on the cheek. I kind of feel bad because I do have my fiancé and wanting a gf at same time wanting him. But when got off work I told my fiancé I made a friend at work but ironically he knew who I was talking about. Which I didn’t tell my fiancé which I feel guilty and feel scared to tell him that I want him and have a gf at the same time but not someone off line. Help please? Plz no rude remarks.