Forever Writing You

Question: My ex-boyfriend (& first true love) is about to get married, but his fiancee is cheating on him. I'm tempted to send him a message and let him know. Would that make me an a**hole?
Looking back, maybe I should've posted my question on the internet first instead of acting on it.
Maybe if I'd just minded my business and let him go as I did before, then I could've focused on my own grief and the sad state of my life.
Then again, maybe he shouldn't have responded...