I hate to look at a pair of newlyweds and say their marriage is definitely DOOMED . . . but dear GOD, this marriage is definitely doomed.

Last week, 21-year-old Mohammed Ahmed of Lincolnwood, Illinois and his wife were in Orlando on their honeymoon.  And while they were there, Mohammed left his new wife in the hotel . . . to secretly go get a PROSTITUTE.

Mohammed responded to an ad by a hooker on Backpage.com.  It turned out to be an undercover sting by the Polk County Sheriff's Department.  Mohammed was one of 92 people busted in the sting.

His new wife found out he'd been arrested when he never came back to the hotel, and she called the cops to report him MISSING.  They told her he wasn't . . . he was actually in one of their cells for soliciting a prostitute.