She calls you up late at night complaining about the latest jerk thing her assenine boyfriend did to her. You’re busy and you can’t use your phone for very much longer, but you stay on the line and listen because she’s crying, she came to you, and you’re a nice guy, damn it! If he’s not going to be there for her, you might as well be!
Stop. You’re an idiot.
When she hangs up, she’s going to be glad she has a friend like you. She’ll stop being angry at her boyfriend and take this newfound information (your perspective) and use it to reinforce her relationship. The guy, on the other hand, will have no clue, the next time she talks to him, it’ll come out of left field because he hadn’t been thinking about it like she has. She will surprise him, and no matter what you said (even if you gave her bad advice, you sly, jerk of a bastard devil, you), she will alter it to help her work on her relationship.
But the guy, because he has no clue, will not help, and the relationship will drag on longer in the same rut, which will cause more late-night phone calls.
The relationship is screwed. By doing ‘troubles’ talk outside of the relationship, she’s getting the fulfillment in her life from someone other than her mate, so she won’t tell him her problems or complain (why should she, she has you), and he’ll still be the same jerk. But eventually, she’ll realize that her mate is lacking in ‘something’ and she’ll call you again, because it’s ‘worked’ in the past.
You, meanwhile, will rack up the minutes, headaches, and sleepless nights without getting any(thing) in return.
She’s coming to you because she has problems. You’re helping her because you want to help her not have problems any longer, but you’re really just making the relationship last longer (in an F’ed up state). Nobody wins. Everybody thinks they win, but two months later they’re back in the same spot.
So the next time a girl calls to complain that men are assholes, just hang up on her. You’ll be doing her a favor.