agree with icod and stirling, these 'flags' are very american. Usually people tend to keep their distance at an office party because they don't approve of their boss'/colleague's behaviour but daren't say anything and feel sorry for the wife but don't want to meddle.
Depends on what you're used to in a relationship but I get small things from my dp, or sticky notes with lovely stuff on them, he even bought 2 summer dresses for me recently and gave me flowers for mother's day (tentatively as I was 8 weeks pregnant by then). So if he continued that it wouldn't be an indicator at all.
And he always wants to look good and is really meticulous and stylish in his appearance, so I wouldn't notice at all.
I guess as women we just 'feel' something has changed isn't quite right. Love the book Blink on tis topic. A gut feeling that something isn't quite right. A look into cell phone, bank account, etc. then proves the theory et voila, Monsieur has been paying attention elsewhere...
It's the criticism and blame, the shifting of guilt onto an innocent wife's shoulders and the constant drip feed of making the wife feel insecure which is pure poison and shows something is terribly amiss.
I have to add that over the years I've also come across a good percentage of women who do turn a blind eye to extramarital activities and cling on to their social status/perceived perfect lives like glue. Even if they inwardly hurt and are unhappy about the situation they'd much rather be Mrs. X then stand up for themselves and re-establish equality and show their kids that a wife's role is not being an unloved doormat but a person with spirit and pride.