I came close to having an EA with a colleague many years ago. We realised a bit belatedly that we were closer than our OH's would be happy with and cut contact right back. His DW particularly was a bit suspicious, probably rightly so.
We don't work together now and only see each other during the football season, never alone. I still count him as a good friend and will occasionally text with news in between times, but always one off short messages, never long ping pong conversations (anymore). i.e yippee I got the job or DS1 was picked for the team.
When writing my messages I check with myself that there's nothing he couldn't show his wife, which shouldn't be necessary but it once was.
Anyway he's text today to wish me a Happy Birthday. Quite a long gushy message but nothing overly personal. My automatic response is to text back "X" and leave it at that. A bit friendlier than a curt "thanks" but doesn't start a conversation.
But what would his wife think if she saw a text message that is a single X, from a old suspected OW?
I can't not respond. He'd worry that I was dead and that wouldn't be fair.