My wife had an EA with an old friend of 33 years. She contacted him on Facebook about 2 years ago. They would talk on the phone occasionally, but when they did it was for 1-2 hours. Sometimes I was there and she would put him on speaker and the three of us would chat. He is an airline pilot and was even going to arrange (with passes) for the three of us to go to Europe. It all sounded innocent.
Not to any right-thinking couple with healthy boundaries in their marriage it wouldn't.