I'm 27 and not married, but I have several friends who are. They're pretty much the same married as they were before being married. Some of them even--
gasp!--hang out with people besides their spouses still!
Based on a long stretch of Spider-Man comics, you'd think that was impossible. But that's just writers being stupid and arbitrarily putting Peter and MJ into this box where they're the only company the other ever has for years. The Marvel higher-ups just found the marriage to be a convenient scapegoat for said writers' stupidity.