My brother and his wonderful wife met online through some sort of dating service. They were "just friends" for quite a while, but they aught fire somewhere along the line. She's his third marriage - and SO different, physically, mentally, emotionally - from his first two. The first left him for another woman, which was okay, but she couldn't have figured that out beFORE she broke my brother's heart? We kept telling him the other was crazy, but he didn't believe us until she finally left ... and got committed - literally, poor guy! Anyway, my current and final SIL is an absolute gem! She even stuck with him through brain cancer. If HE doesn't keep her (which he will) then one of the rest of us will!
And she only "happened" because he was lonely enough one night to click that send button on an ad. So, y'see ... it works for some!