There's just enough drinking and cheating songs around without me adding to them. Unless you've got something better than "Misery and Gin" by Merle Haggard, you're beating a dead horse.
We must stop chasing dollars, stop lying, stop cheating, stop ignoring art, literature, and all the refining agencies and instrumentalities of civilization.
You should always give 100%. If you do that then no-one can ask any more of you. Someone once said to me when I was a kid: 'If you're asked to do ten sprints, by all means do 11 but never do nine because you're only cheating yourself'.
The usual sniggering examples of animal behaviour were brought in to explain cheating. Funny how the behaviour of shrews and gibbons is never used to explain table manners or road safety or gardening, only sex. Anyway, it was bad Darwinism. Taking the example of a monkey and applying it to yourself misses the point that animal behaviour is made for the benefit of the species, not as an excuse for the individual. Being incapable of sustaining a stable pair and supporting children is really not in the interests of our species. Neither is it really in the best interests of the philanderer.
If you cannot work on the marriage or the women is a moron, staying married and cheating makes the most sense because divorce is disruptive to the family life and your bank account.