Only one I know of. I was a bit young, but she was kinda related through marriage. My brother-in-law's brother's wife. I was really sad about it. I still remember her face perfectly. She was beautiful. She left behind two great kids too. Probably around 1973.
According to my sister (who was her sister-in-law), she was being treated for mental issues when her husband's family decided to move 1500 miles away to Florida. A bit of a close-knit clan my sister married into, with a very dominant father. So he dragged the family to a small town in Florida where I don't think she kept up her treatments.
Now only in the past couple of years, I heard another rumor. Her husband, let's call him Tim (no real names here), wasn't exactly a manly macho looking guy, a bit the opposite. And neither was a good friend of his from back where we all grew up. Let's call him Randy. Randy, as a teenager used to live with Tim's family for a while. Randy I knew better since he stayed around where we live and I grew up and saw more of him. Randy always dressed special, a little more "fashionable" than the rest of the congregation. He married, but his wife always looked unhappy and frustrated. A friend of mine said once "it looks like she's never gotten any". Others might call her a "beard".
Not that being effeminate or fashionable means somebody is gay. But let's face it. Those traits aren't uncommon among gay men. And not to judge if they were.
So, rumor was Randy and Tim were having a gay affair. And I know nothing for sure as neither has come out and both are still JWs. Anyway, rumor is Randy and Tim were on the phone together when Tim's wife picked up the phone, listened in, discovered the relationship, couldn't take it, and killed herself.
I believe my sister about the mental issues. Now whether mental issues + betrayal had anything to do with it, I don't know. I hope not, for her sake. That whatever she was feeling, betrayal wasn't mixed in. That somebody else's actions didn't push her over the edge.
She was a JW at the time.