I honestly don't - where are they, if they do in fact exist 
The blokes I do know who are single go a bit like this:
Exhibit #1: Very young looking 60 yr old with issues and penchant for kinky/weird stuff (maybe gives some insight into why he's been on his tod for the past xx years ?!)
Exhibit #2: 40+ yr old "artist", good looking lad, sporty, etc. No money, commitment issues, cannot stay with 1 girl and is always traveling.
Exhibit #3: ex of mine. Seems pleasant enough, wholesome even.... turns out to be freakin' nut case with so many insecurities he started inventing stories 
Exhibit #4: another ex... to much going on in his life, with all the sport, going out and pleasing himself, he just doesn't find the time for a GF.
Exhibit #5: my BIL, aged 40, house owner, cooks, nice..... why he remains single is one of life's mysteries. Not my cup of char but I reckon he's just not man enough to want a woman.
Exhibit #6: my dad. nuff said.