Came out to my foster brother

So, about two weeks ago, an incident arose between my brothers wife and my ex wife. Little bit of back story, myself, my brother, and my ex wife, all lived in the same foster home. None of us are biologically related nut that is where I met her. When my brother got heavily into drugs I had cut all ties with him. Now, after 13 years, I find that he has cleaned himself up, is remarried with 2 pretty cool kids, and is living 4 blocks down the road from me. So now we hang out whenever we can, his wife and mine are good friends etc etc. Any way, our wives were talking and apparently my ex found out we were spending time together and told his wife that was a bad idea as my divorce was caused by me abusing her and being in and out of rehab. He knows me well enough to know that I've never hit a woman and never been to rehab. She however dosnt know me that well and out of concern asked my wife if I had ever hit her. She knows better now. At any rate I decided to explain to him the real reason for my divorce. She couldn't handle my being a crossdresser and cheated on me repeatedly. He was shocked but very accepting. That's the one thing she has against me but she lies about me instead. So not only did he tell me that he thinks no differently about me, he says that a lot of things make more sense now. And I'm still allowed to paint my 6 year old nieces nails. He also said if he hears her talking about me again he is personally going to file a defamation lawsuit on my behalf. Sorry for rambling but this is my only real place to share this.

Try not to get the law and lawyers involved if you can keep from it.
Essentially he knows the truth now and everyone knows your Ex is a liar and making stuff up about you so she has no power over you.
The more your ex squalls about you the more they will just think she is a nut bag and pay no attention to her.
Filing a suit only causes more trouble and brings you into the picture and we all know one files a suit everybody gets drawn into court and you all look guilty of something.

Ronnie, It's great you were able to get your exes lies out of the way and head towards acceptance.

Ronnie, I enjoyed reading your post and happy your brother and his wife are accepting.

You’re going to have a hard time with a defamation lawsuit without her comments being published, and you having to prove damages. If she has said that to your employer and gotten you fired, that’s one thing, but simply spreading rumors isn’t likely to result in a satisfying conclusion for you. Best to just let it go and rise above it.