It's perfectly fine not to get married cause marriage isn't for everybody.
However, the obsession that both manosphere and radical feminist types have with proving that marriage is the worst thing on Earth and that it enslaves men/women is a bit excessive and hyperbolic.
Obviously, there's bad marriages out there but there's also bad relationships that don't involve marriages at all. Just look at how many baby daddies and baby mamas who never married are stressed out and angry at each other or how many unmarried fathers are going broke over child support.
Also, the average single man or bachelor is not a casanova. It's been statistically proven that married men have more sex than single men. For every playboy bachelor who's getting p*ssy every other week, there's 3 more single men who are getting little to no attention on dating apps, little to no attention at bars/clubs, and little to no sex with random women(excluding escorts/hookers).
In essence, marriage is not a necessity but not being married won't automatically give you a stress-free life either.