I don't know if this is true across the board. I don't feel that way entirely, more along the lines of "I'm stuck in this situation; kids, a marriage where I get no real benefit, I just want to be free and do what I want and not have to bow to their whims."
I know several people, right now, that have been divorced for some time (5+ years, and in one case 10+ years) and don't even date or have interest in dating. Their motivations seem aligned more with mine than wanting a better mate - In fact, If I end up getting a divorce (we have agreed to try and work it out, again), I have no interest in dating again, at least not for a while.
FWIW, I'm 38, and the people I'm referencing are older than me, some as much as 12+ years older, so maybe it's an age thing.