This is a verse that is so, so, so misapplied. It's generally applied to marriage, right? Husband, wife, Jehovah? This was a recent research session for me. Let's see what it's REALLY talking about:
Eccl 4:7-12
I turned my attention to another example of futility under the sun: 8 There is a man who is all alone, without any companion; he has no son or brother, but there is no end to all his hard work. His eyes are never satisfied with riches. But does he ask himself, ‘For whom am I working hard and depriving myself of good things’? This too is futility and a miserable occupation.
9 Two are better than one because they have a good reward for their hard work. 10 For if one of them falls, the other can help his partner up. But what will happen to the one who falls with no one to help him up?
11 Moreover, if two lie down together, they will stay warm, but how can just one keep warm? 12 And someone may overpower one alone, but two together can take a stand against him. And a threefold cord cannot quickly be torn apart.
Notice, there is no mention of a husband and wife here, but "son or brother", yes. And what does the threefold cord apply to? Defending oneself. Hard to defend yourself by yourself. Easier with a second person. Much easier with a third. This has NOTHING to do with marriage and having Jehovah as the third cord.