WaxyZ - I thought that I would chime in as I have similar fears as your wife about public behavior and job/career safety and we have had to make decisions/compromises around this (still in progress).
Our situation: I am married and live with my husband (MrS) and my boyfriend (Dude) (who was/is my husband's best friend). We are out to our friends but not publicly - although we are transitioning to be out "socially" i.e. to "friends of friends"/social acquaintances.
For me the privacy issues breaks down to several parts:
1.) How Dude an I interact with each other when we are all out.
As it stands now - no PDA when we are in public in either the town where we live or the town where I work. PDA ok in public otherwise - such as when we go into the nearest city for the evening (unless I happen to recognize someone that "shouldn't" see). PDA ok when we are socializing with our friends at someone's house, even if there are "outsiders" present (this is the part that is still "in progress" - I'm jumpy about this).
Now since the "no PDA where it could threaten my career" is MY rule and PDA with Dude would involve me participating this part is easier to resolve (this rule chafes with Dude a bit - but he understands where I am coming from).
2.) What happens when Dude starts dating others?
can do whatever they want in public.
So, obviously, when he is meeting/starting to date someone they have to know that he is in a relationship with someone else and she (me) is fine with him dating others (i.e. he is not cheating). BUT the details - that his girlfriend (me) is married and knowing who I am and that having that be public knowledge would be damaging to my career? At what point do you trust a relative stranger with that information? If something happens and their dating relationship goes south I worry that this potentially hurt/angry person could use this information against him/me. (Yes, part of the answer is to not date crazy women
...but sometimes that is not something you can tell right off the bat.)
I think it is likely that he would be dating people from our circle of friends who already know - so this might be worry over nothing. If he meets/dates women from outside of this circle I think we will just have to take it on a case-by-case basis. (Basically I will have to be able to trust his judgement about trusting another person with my information which could be damaging to my career...at a time when he will likely be caught up in NRE and she will still be presenting her best "dating" self to him - ohhh, scary
3.) What happens if MrS starts dating others?
It's a good thing that this is less likely because this has all of the "public PDA" issues from #1 (with the added complication of it being MY issue and not their issue - making a "rule" for someone else's relationship does NOT sit well with me...but if you date a married man maybe you might expect some baggage to be attached, no?) AND all of the "metamour information" issues of #2.
Best Case Scenario: Maybe he will only date married women who have their own public PDA/metamour information issues?
Oh well. Here's hoping my boys only date sane women who care enough about them to respect a request for discretion on my behalf.