Hi and welcome 2 kitkat!!!
My grandfather cheated on my grandmother. She knew it! But they stayed together over 60 years. Their only daughter was married over 70 years to the same man. I've researched recent articles on this subject, "Till death do us part?" for a manuscript. 1 study focused on [Divorce-Prone individuals and the question of why some persons fail in 1 marriage after another; serial marriages; etc.] 1 expert said marriage failed because of 3 issues: self-involved narcissists; those that are compliantly depressed; and life's unforeseen changes. Another said between 1960 and 2004 the number of unmarried couples increased from less than 1/2 million to over 5 million. But many Ph.D. folks think women stay in marriages because of the children. Broken homes really mess up the kids, for life. I tend to agree!!!

P.S. If the kids are grown and you're unhappy, chuck the whole thing and enjoy your life!!!! Me thinks!!!