Not really. At least not for most of the guys I know, most of which are not intent on getting married to my knowledge even though most of them have been in a committed relationship for years with the same woman.
And the reasoning is simple. Commitment is in the mind, not on a marriage certificate. None of them is going to risk their financial future because some blowhard has asserted that you can't be committed without being married. The buy-in for marriage is damn expensive and offers negligible benefits, and so fiscally prudent guys have decided against it.
At least among the men I know, not getting married is all about asset protection and a number of them have been divorced before. And more and more women seem to be getting comfortable with this state of affairs. Getting married in an already committed relationship just gives the woman the wrong kinds of incentives and arguably weakens the relationship. After all, after they get married the woman can just "cut and run". Break-ups are actually pretty equitable if you aren't married, no matter how long you've been together. It is hard to say the same about divorce.