BW,

Don't get me wrong, I don't think it's a completely bad analogy, but like any analogy, it will only get you so far.

What I do like is the "dysfunctional couples" you mention and how such dysfunctional relationships go on for years and years. In such cases, though what influence can a friend/competitor really have?

Here's a situation using your analogy which might be familiar: Suppose you, as the friend, come into the house, shoot the current BF/Hubby and boot him out because he killed your inlaws. Thinking he was mortally wounded (you followed the blood trail to the neighbor's yard), you help the woman find a new boyfriend who, it turns out, may let her watch some TV and listen to the radio but can't hold a job, buy groceries or pay the rent like the last guy could. More importantly, neither you nor the new boyfriend can protect her from the ex you shot but didn't actually manage to kill. He comes around from the neighbor's yard and gives her the good-cop/bad-cop treatment of threats + inducements when you and the BF aren't around, which is quite often. Then there's the new boyfriend's old-boys-network of friends who are fleecing and exploiting the woman so she can't even buy food with the little bit of money the new boyfriend hasn't squandered. The (probably feigning) sympathetic ex gives her a bit of money and a shoulder to cry on. The woman starts to think maybe the ex wasn't so bad after all and she blames you, the friend, for bringing about this course of events and screwing up her life completely. You, as the friend, can't catch the ex and finish the job and you can't seem to convince your buddy, the boyfriend, to change his ways. What are your options?

Sounds kind of like an episode of Dallas. Maybe studying soap operas can give us some insights here!