I only got halfway through it but it was about a rather large man who I believe was American. He was married and had kids to a woman who was kind of cold and didn't really love. Eventually, he divorced her and married some jubilant, younger woman who I think was a bit on the hefty side. I think he lives on a farm at one point, I couldn't say if he was married to one of the two woman or not at the time.
The main focus of the story is when he travels to Africa with almost nothing on his back as some sort of self-discovery type of thing.
I wish that I could be more descriptive, but it has been six years. I am pretty sure that it was from the 20th century, probably somewhere from the '50s-early '80s, and it was relatively well-known because it was on a list of books that high school students should read
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"Anybody interested in grabbing a couple of burgers and hittin' the cemetery?" -Royal
"Oh sure, walk to the sun"- Guybrush