A play on the famous saying, "life's a beach". Usually uttered by married men who, upon getting married, realize the woman they've committed their fucking lives to suddenly becomes an unrecognizable, nagging, sexless hag that they are now bound to by law for eternity....WTF.
Gary: "Dude, how's married
Jim: "Wife's a beach
Gary: (muttering to himself) "..poor bastard"
Jim: "Well at least I got this cool shirt from WifesABeach's zazzle store"