How to tell my friend that I slept with her bf?? ?

My friend has been with her dude for 4 years. I lost my house during the pandemic so she let me stay with her. I always had a crush on her boyfriend way before they got together. He came on to me last month and everysince then we been messing around while she’s at work.. she told me “they getting married”  and I had got sooo  “jealous” kind of.. should I break the news to her?? I’m jealous I wish my friend the best but I just hate she’s moving on with her life she got a nice job like why her??