< UNPC type=sexist >Stay in shape, wear proper clothes and makeup and not be a bitch. Prevention is always better than the cure. < /UNPC >
Not to be a "White Knight" here but that is a two way street.
A woman in my gym really keeps herself in good shape. She is in her early 50's and has a incredible hot bod and still very attractive facially for her age. A true MILF. Saw her hubby with her one day...280 lbs ish-just plain obese...unkempt..just a plain hideous slob. She has been complaining more and more about his weight and his slothiness to my GF and starting to really resent his not taking care of himself.
Combination of fit men eyeing her up all the time and outright flirting with her(and her returning it) and her growing displeasure about her hubby...we can see a divorce coming....My gf and I are taking bets for when it happens.
Quick summary to women AND men..don't let yourself go....because if your spouse is remotely attractive others will give them attention...at any age.