Help! I want to send anonymous letter to OW

I want to send the OW an anonymous letter so bad. I have it all typed out, in envelope, and stamped. She is the 4th women in the past two years. She needs to know the truth, I wish someone would have told me. She may not believe it, however when it starts to happen the same way she will reflect back and maybe it won't take her as long. It is all new, he dropped off my furniture on Friday and he has been with her for 3 weeks, after he D&D with me. I found out via his sister that he is seeing someone new, she had no idea he was with me for 1 1/2 years off and on. I found the forum after I found that info because it didn't make sense. He dropped me via a text and has ignored me since. He emailed me and said he was dropping off my furniture I borrowed him... Help! Thoughts?? I want revenge so bad!! I want to know your experience. Have you been here, done that??