Website & Phone:
You and your mate/partner/spouse each put your side of a dispute you're having with each other, and visitors and members then vote and comment. And that's it, but simple as it sounds, it does after all encompass a large percentage of the way that couples spend their time: arguing over who's right. Like eating and sleeping, it's something we all do. So this is bound to be an attractive site for almost everyone.
There's no need to be serious, and in fact I think you're a lot safer doing this for fun. In any case, you know in advance what most people's comments are going to be: "You don't have to change just for him/her", "You do have to change for him/her if you want to keep him/her", or "You don't want to keep him/her because he/she is an [enter descriptive term]".
You can post and vote anonymously too. I didn't figure out the advantage of registering but there seems to be one. Let us know if you use it and what it does.
It's a harmless piece of fluff if you treat it lightly. And you might consider putting your partner's side of the argument on her behalf, without actually showing her the site, just in case it turns out that nobody agrees with your side of it. No point in taking unnecessary risks.