haha ohhh man.
Well I guess the older generation is different than the younger generation:shrug:
I actually know many men, in fact most of the guys i know are like this, that would be happy to have that one partner for themselves whom they can be with for the rest of their lives (In their early or mid-twenties). Their attention span may just be a bit not too great, or they may not have the means to get married right now, and thus decide to party till they can. They can go from girl to girl looking for that "one", falling in love with every other girl, just like some girls can go from guy to guy, or latch onto one guy for years hoping they'll finally notice them and take them away. Needless the say the problem lies on both sides here.
However, I do know some guys my age (in their early or mid 20's) who have gotten married already and some who are very ready to get married.
The variety thing is definitely an issue for guys. But sometimes it's not. It can really depend on how interested we actually are in a girl. If we're not sure how we feel or don't really like a girl, variety could be an issue. It could also depend on how good looking our current girlfriend looks to us. This may be hard to hear, but commonly the issue isn't whether or not the person we are dating is more compatible to us than someone else out there like it is for most women, but whether or not we could get someone who is better looking. Again, this is only if we are not that interested in the first place. Remember though, it's not about how good a girl looks objectively, but how good she looks to us.
However, if a girl gives us enough peace (or if we are compatible as women like to say) then the physical looks wont matter much at all. That is why you may be surprised to find that some guys you knew earlier in life ended up marrying a girl who wasn't that good looking.
So in the end, the guys who are still unmarried at 35 were probably the same guys who in their 20's didn't think about getting serious in a relationships at all (of whom I only know like...4-6). Those who did, when they finally had the means to, got married. So unfortunately, you are pretty much left with those who have been saying their entire adult lives "I'm not ready to get married". That's why I suggest the Catholic dating site above. You'll know a persons intentions before you start to date. You wont waste your time.