Boyfriend Cheated...I'm Attracted to someone he KNOWS Should I Go There?

EX of 1 day knows this guy but they are not really friends. Just hye and bye and a converstaion here and there. The boy is severely GORGEOUS and on top of that he's an identical twin. I flirted with him before. I can feel the attraction. I found out my Ex who I broke up with today cheated on me 2 days ago. I told the twin he was so handsome but don't tell my ex (I was with my ex at the time) He smiled and said thanks and he wouldn't say anything. He hasn't because my ex would have been so mad. I brushed up against him and said excuse me (purposely he knew and laughed kinda brushed my against him) I am so attracted to him even more than my Ex. Should I give it a shot but tell him to keep it a secret. He didn't tell my ex about me being flirty yet. It's Over Anyway. My ex is mad becuase he thinks I'm his. Should I secretly date the new boy. He always looks at me and speaks even when I was with my ex. We use to crack jokes when my ex was away doing something. I just want to have with him (No strings attached) I want him BAD