Protect your marriage. I do not become friends with, or invite to my house, people who do not share the same marital values as I do. I am anti-divorce and anti,cheating.

There was a study that showed people who had divorced friends were at an increased risk of divorcing. This would imply that people are not immune to having other people's ideas influence their personal life.

You need to tell your wife that her friends are bad influence. Her friend openly disrespects you to your wife, Point 4, and is behaving as an adversary to your marriage. And the guy, No. 3 is also trashing you in your own home. Doesn't get much more disrespectful than that.

Your wife is at the midlife crisis stage where these toxic people will influence her to the detriment of your marriage. Time to set a boundary and get new friends.