There are as many answers to that question as there are guys who make the statement.
Maybe some of them have been through a bitter and hurtful break-up and feel especially burned by having to pay their ex alimony because she is unwilling to get a job to support herself.
Perhaps they were nagged mercilessly and the new found freedon to do as they please is a refreshing change.
Maybe he's had a couple too many strike outs lately and he's benching himself to rest and re-evaluate his priorities. Maybe change what he looks for in a mate and then regroup and go hunting again.
I think most all of them boil down to a similar scenario. The guy in question was sure that the girl he married was 'the one', or he wouldn't have married her in the first place, and now, after being proven wrong for whatever reason and having seen the difference, he may be a little more cautious to trust his gut.
Your question is impossible to answer with 1 general statement because it is like asking why somebody finds one girl attractive and not another. Every path has it's own story, and the changes in direction and choices made are all for personal reasons, which is what makes us all unique.
and again and again and again! If I get married it will be the third time and I'm only 40. I'm not giving up I know the right man is out there somewhere. Of course the clock is ticking and I'm not getting any younger, but I am getting wiser! Where are you Mr. right?
A lot of men who have been married want total freedom to do what they want when they want with whom they want. And, they don't want to answer to anybody, get bitched at, nagged, have a woman try to change them. And, there are plenty of women who will hop in the sack, so the guys feel they have it made.
Then there are the guys who get burned, don't learn their personal lessons from it spiritually and are gun shy or so battered, they become emotionally crippled.
Then, the good news- There are guys out there who want a LTR and marriage. These are the guys who love to wake up and snuggle their woman, take great care of her, putter, make love, have fun, be faithful, loyal and supportive. They love the joys and comforts having a woman and love to be married.
I spent the last 18 years being a devoted mom. Never had a man in my bed when my son was here. I miss living with a man, miss being married. Miss the comfort, security and that special feeling that comes from having a good Honey by my side. So, I am looking. I thought I'd found it when I dated 1 guy for a year, but he just wasn't the right man for me. It was almost a year ago, so I am on the hunt for a good man. Might feel like a needle in a haystack-but I would be happy living with a good man and don't feel I have to marry, but would like to get married down the line. There is something special that happens for me when I am actually married--it creates a special bond I have only found inside of marriage. I'm done with playing the field. Inside of marriage there is a lot of freedom- to make decisions together Re monagomous, swing, whatever.
Needles in a Haystack! but they're out there and Serendipity could happen at any time!