Disclaimer: I don't own Teen Titans and I am not making any profit from this work.
Contrary to popular belief, and the teasing of the guys, it wasn't love at first sight. In Robin's opinion, that would have been very weird of him. Okay, Starfire was impressive at first sight, but she was also pretty scary as well, and he hadn't been all too sure whether he was dealing with just a freaked-out alien or a villain. He hadn't been sure removing the cuffs was the best idea on Earth either - he supposed it was just lucky that she'd proved him wrong.
With the benefit of hindsight, Robin supposes that he probably was pretty obsessed with Starfire early on. It hadn't taken long for her 'friend' status to be upgraded into the ever-ambigious 'something more' area. But, at the time, he hadn't really taken the time to figure it out for himself. He had thought that Beast Boy and Cyborg were wrong, and Starfire was just a friend - okay, a best friend, but not a girlfriend - and that they needed to grow up.
Only, with the benefit of hindsight, he had been wrong.
He feels stupid, sometimes, at how obvious he must have been to absolutely everyone else (apparently even Starfire, which is the most embarassing part) and yet how oblivious he was to the whole charade himself. His need to protect her, his need to make sure she understood everything that was going on and that the guys weren't teasing her too much, his need to make sure she was okay at the beginning and end of each day, his need to check that she was happy and his need to correct things if she wasn't...it was painfully obvious now, but it hadn't been then.
And now, he wouldn't deny what he knew for the world.
He knows he probably has the weirdest girlfriend in the universe. At least the weirdest humanoid one. She drinks mustard like other teenagers drink alcohol, none of the team have heard her use an English contraction in her life, yet when Cyborg made a translator for when they had to visit Tamaran, it turned out Starfire was quite the slang-user in her own language. And after Tokyo, Robin still resists taking her on vacation too much, in case she went around kissing the locals to learn.
About the only thing normal about Starfire is that Robin really, really hopes he'll never have to do the Earth custom of 'meeting the parents'. Because he's pretty certain that Galfore would slaughter him on the spot for breaking some obscure Tamaranean rule about the royalty and common-or-garden alien people.
But contrary to popular belief, he still isn't Starfire's primary source of knowledge on Earth customs. Surprisingly, she stills tends to go to Cyborg with her questions than Robin - perhaps because Cyborg has a no-nonsense way of explaining things that can sometimes get Robin flustered. Starfire's innocence doesn't throw Cyborg in the same way. Sometimes Robin's grateful for that. He doesn't want to know some of the questions she must have asked before.
And contrary to popular belief, he keeps their relationship in mission as professional as possible. He won't let her - or anyone else on the team - get hurt because he's preoccupied with his girlfriend. And he knows it sounds cold, and sometimes he goes a little too far and gets the cold shoulder for a few days from the others, but most of the time it works. And she understands. And even if she is a little put out by it, he makes up for it later.
(Though he suspects she spends too much time in his room - that pet maggot thing, or whatever it is, keeps finding its way into his room and will not be persuaded that his clothes and bag are not pet beds.)
And contrary to a lot of popular belief (though generally by their acquaintances outside the team, as the team have to live with the explosions) his and Starfire's relationship is not perfect. It's not champagne and roses and watching the sunrise. A lot of the time, she's difficult, and he's impatient, and their work gets in the way. Sometimes she doesn't understand something she really should by now, and he loses his temper, and they fight. And Starfire's a fighter, above all.
Maybe that's the hardest thing to handle. Starfire is a warrior, and her gentle and - okay, sweet - demeanour sometimes lets Robin forget that. When she wants to, and when she's angry enough, it becomes clear that she's from the same family as Blackfire. Starfire has her own attitude occasionally, and when she gets that worked up, it often gets ugly. And when they fight, it sometimes turns absolutely hideous, and an enraged Raven has to pry them apart and banish them to opposite ends of the Tower until they've calmed down.
Thank God for telekinetic powers.
Starfire is passionate and energetic, and sometimes it's hard to handle, but more of the time it's a blessing. She lets Robin let go; she teaches Robin how to be a kid again. She's funny, and she's sweet, and if sometimes he's laughing at her rather than with her, she allows him to, for the time being. She's sly, too, and when he's overworking, she'll appear with questions and confusion, and it's only much later that he realises he's teaching her something she's known for ages. Like the time she convinced him that the microwave didn't like her, and he ended up teaching her how to use the different heat settings, even though Raven had taught her that years ago, when she'd first arrived and nearly blown up the kitchen.
The princess has been a breath of something new, and it's brought a little spice to their world. Raven's favourite nickname, in moments of dry wit, for Beast Boy is still 'clorbag', and Robin is suspicious of the amount of times Cyborg has yelled in Tamaranean at their video games when Beast Boy is winning. Though Robin himself has picked up the odd phrase, it's less swearing and more endearments.
Contrary to popular belief, it's not easy, being with Starfire. Sometimes it was even easier when Robin lived in his own little world of obliviousness as to how he felt. Sometimes, dealing with Starfire was a lot easier when she didn't know the access codes to your bedroom door and wouldn't have entered even if she knew them.
But then, popular belief is right in that it's pretty damn amazing, when you get right down to it. And Robin knows, that whatever people believe, he's not giving it up without one hell of a fight.