Men with young kids at home should strive to be the best dad possible by staying married and always keeping peace at home. Families require stability. Unless their wives are extremely open-minded, this means they are limited to a lifetime of monogamy or secret affairs.
For a married man to have a successful secret affair:
(1) He needs to have a job with varying hours. This allows plenty of time for a mistress without arousing suspicion.
(2) His mistress has to understand that he's married and be quiet when his wife calls. A husband not answering calls or refusing to talk is just plain dumb.
(3) He needs to only have safe sex or make sure that he and anyone he's having sex with has been tested for STDs.
(4) Never bring the mistress back to the family home. A wife would consider this the ultimate betrayal.
(5) Make sure the relationship is mutually beneficial. No drama--only fantasies, romance, and fun. The wife is the one he lives his daily life with. His mistress is his "secret get-a-way from reality" and he should spoil her generously.
(6) Hiring a professional call girl is the safest route. Wives often desire revenge against husbands who have other "relationships" on the side. Whereas, should he ever get caught, the wife is much more likely to forgive him for hiring a hooker.
Sometimes having extramarital affairs can enrich your marriage. Seriously. They remind you why you love your partner so much, and, by experiencing another, you can show that renewed sense of love when you get back home. The key here is to do it without risking your current relationship and lifestyle. This can be tricky.
Personally, I am polyamorous and am honest when I feel the need to go elsewhere. I also understand if a partner feels the need for variety. Nobody owns me and I don't own anyone else. Sadly, few people are able to be that honest within their marriages without their partner freaking out. :(