Yeah, that's what a lot of men like to think -- that's part of how they keep themselves "contented". And J-Lo, being the shallow tramp that she is, is not a good example. Level-headed professional women who remain single will generally end up a lot happier than self-absorbed, serial-marrying, bed-hopping (between and during marriages) J-Lo.
In reality, there are certainly more miserable married and formerly married 30-something women than miserable single 30-something women. Instead of moping around about being single, single women should be glad they maintained control of their own lives, and are not stuck in the unenviable position of many married or formerly married women. Marriage can be great when undertaken for the right reasons, but it's no guarantee of happiness, and also carries substantial risks of extreme unhappiness.