Its really quite simple why so many men have a suck buddy - they need to get their rocks off in other ways than masturbation.
As a cock sucker of many years you see the pattern, commuter guys tossing in the corner of the gents on the way home, knowing the little lady is going to be sexually frigid and he feels horny. And along comes guy who gives him head, no strings just suck cum and swallow.
Once they realise they can get a guy who just wants to suck cock, on their terms, it all falls into place, and, technically its not cheating!
The latest guy to use my services is 28, 3 kids, wife not into sucking a "dirty" let alone getting it to cum in her mouth then relegating sex to Saturday night every other week "because".
He came to me on recommendation - yes some guys do chart and do swap notes and do confess to not having a randy 7 nights a week fuck fest with their wives. He likes to chat, get sucked off and then maybe hang about and do it again. For him its safe, its on his terms and because I am an older guy I'm not going to cause waves, and, am open to suggestions from him about what he would like done. Unlike his wife I always swallow, have no qualms about sucking his "dirty" dick and know that he goes home satisfied.