Living alone is not is necessarily lonely. It's often quite nice as long as one has a circle of friends. I'm not sure why there is a fixation on marriage as being some sort of ideal. It's great if a couple can stand to be with each other for 30 years, but to do it with suffering is not noble, it's just foolish. Also, your kids will be fine if you divorce. The working class, with its high divorce rates, has seemed to figure all this out first.
1'Americans Living Alone: Meanings and Implications - Richard Wolff and Dr. Harriet Fraad.