I admit I've rarely written happy relationships (though is has been a while since I last wrote) people that help me write suck me back into tragic romances but stable fun ones are nice as well though I've only got maybe two couples I've written in happyish relationships. While they can be fun to write they are not fun to go through the tragic ones I mean.
Agreed it can be done and done well one of my favorite book series the main relationship is happy and supportive and I don't get tired of reading about them and I love it when they interact with one another, guess you need a specific mindset for it, I'm not sure.
Thank you my mom really deserves it the last relationship she was in brought out the worst in them both so I'm happy she's with her current boyfriend they're very happy together and whenever I visit they always joke with eachother and make up quickly after fights it's pretty adorable to me and I'd be lying if I said it didn't set a bar for me in what I'd like a relationship for myself to be like 
Eh, I don't find tragic relationships fun. I've witnessed and experienced enough dysfunctional (and even abusive) relationships growing up that that's not what I want to write about, or even see for that matter. Sorry, that's not to say my couples don't have problems at all. Of course I try to keep the relationship realistic by giving them problems and challenges, having them fight and disagree, and have them more snap or lash out the way most real people would when under the same stresses, etc.
I just don't like introducing tragedy, drama, and angst for its own sake. It's a means to an end for the story at large, or to create the character development they need, or to ultimately bring them closer together, not drive them apart for the sake of enjoying their fighting, angst, tears, etc.
There are ways to have tension in a relationship - or surrounding a relationship - without making it tragic or affecting the fundamental dynamic between characters.
Edit: For example, characters could have different goals in life that pull them in different directions. There could be a difference in race, or culture. None of these things have to lead to a sad ending for the characters.
I agree. I'm not saying fictional couples always have to be perfectly happy. That they should never argue, disagree, etc. No, because that's how real people interact, and it really would be boring otherwise if they never had any problems or challenges to overcome. I just don't think soap opera sadness or some new contrived Deu Angst Machina is the solution.
Like, I find it funny that Gaider says happy couples are boring when DA2 includes a very interesting and fun one. I thought Aveline's and Guardsman Donnic's relationship was very sweet, funny, and interesting without it being mental hospital dysfunctional like all of Hawke's relationships. Aveline's hilarious attempt at wooing Donnic came from how quirky she is as a character, not how creatively angsty the writers thought they could make the situation. I like how when they get together, other characters tease her about being able to picture them having a whole brood of red-heads able to lift a cow. Or how she gets offended that Donnic goes to Fenris' mansion to play cards once a week but they didn't invite her, and they say they would have but she's just so... competitive. And how they disavow all gambling in Fenris' mansion. O:-)
To me, what makes a couple interesting is how interesting they are as characters, and how their little quirks and whatnot play off each other.
Like you said, I just don't think relationships should have to be made soap opera tragic or dysfunctional just to be interesting.
Unfortunately, happy relationships (in media settings) are boring. It is rare that you see a completely happy relationship throughout an entire movie/book/series. Usually it starts out happy then turns bad (possibly working out in the end), or starts out bad and works it way to happy. If drama did not lead to an interesting romances we were actually see more of them, not less.
But Gaider is not a mindless consumer that just watches fictional relationships that other people wrote. He's a writer that creates them too. Like I said, there seems to be this common belief that fictional relationships either have to be soap opera tragic, dramatic, or dysfunctional just to be interesting, or they're completely generic and boring and let's fast-forward through the smiles, teasing, and playfulness to get to the angst, melodrama, tears, etc.
Besides, like I said, I'm not saying couples have to be completely happy without problems. But far too often writers create this false dichotomy that a relationship has to be either generically boring and lovely, or it has to have some grand, dramatic, contrived sweeping tragic situation to be interesting. Of course a happy (or even functional) relationships will come out bland and boring if you go in with that attitude. And far too many writers do.