Welcome!
Hey.... whatever works for you.
Please, no "buts." Those are ideal ages for you and your sexy wife to have a hotwife / cuckold husband form of marriage.
Very good. It sounds like you have the right attitude toward your marriage, and your sexy wife has been taking action, accordingly, to broaden her sexual horizons thus increasing both her sexual and psychological satisfaction.
It's very positive that your hotwife allows you to watch her fucking your friends in front of you, her cuckold husband, and... in addition... that she treats you well.
That's OK. It's perfectly normal for your wife to kiss her lovers — and if she does that in your presence, that too is positive. I suspect your negative feelings about that are a result of you feeling that you, somehow, should be in charge of your wife's sex life. But, that's not part of your role as her cuckold.
Yes.
Probably there are some who do and others who don't.
Because kissing, including deep tongue-kissing, is a natural component of human sexuality. And, it can be an expression of affection for a lover carried out in public, or in front of a cuckold husband (you, in this case), without any need to take the time to undress first.
Hotwife / cuckold husband marriages tend to work best if the hotwife is the dominant partner. I suggest moving in this direction by introducing your sexy wife to:
Real Women Don't Do Housework
Real Women Don't Do Housework
(Lady Misato, the author of this site, notes that the title is somewhat tongue-in-cheek.) Here, I suggest your wife start with the "marriage quiz" (or not, her choice), then work her way down through the chapters listed at upper left, starting with the "Introduction."
Doing so may help you and your wife come to a mutual appreciation that not only is it her privilege and prerogative to date, seduce, and fuck whomever she wishes, while you agree to remain faithful to her (as I gather you are now doing), but also to kiss and do whatever else she wishes to do with her lovers, while you are fully accepting of that.
The more you bring yourself to accept that it is your wife's privilege and prerogative to do whatever she wishes with her lovers, while you support her with that to whatever extent she needs, the more you will realize the fruits of the saying: "If your wife is happy, you will be happy too."