Even identical twins aren't identical, I knew two and one had a gap in her front teeth from sucking her thumb too much as a child, and another two with one who's nose was a tad bigger (from childhood exploits up there). However if you're truly having trouble then buy your girlfriend a necklace, hoping she'll wear it all the time. If that doesn't work there are bracelets that you put on and let your arm grow in to, but it takes a while before you can't get them off, however there are also woven bracelets you can't take off, as well as hair dying options that you could try to talk her in to, any little token that will always be on your girlfriend will do the trick (nose ring as a birthday present anyone?)

if OP was far away from her I would e understandable.

I'm kind of surprised this doesn't have more YDIs. Telling twins apart is a pain, but after three years you have to have noticed some personality quirks or mannerisms or even fashion tells. Hell, even the way your gf looks at you vs the sister should be a clue.

If she's an identical twin, she should be more used to this by now and be more understanding. Also, there would have to be more info for me to place blame on you, unlike other people that voted YDI. We don't know how these girls dress or what they look like, etc... I was best friends with some twins in college. One set, there was a girl with a birth defect so that made that set obvious... but the other set, even as a bestie I had trouble until one got a haircut...

Keevarou, you are by far one of the kindest people on here, I've never seen you post anything negative! keep it up sir! :)

Ménage trois?

(addressing the language argument) My girlfriend's first language is Korean, and yet she is the top in her class for all her advanced level English classes at a major university. Sometimes it is better for English not to be the first language, as long as the person isn't still in the process of learning. Take me for example, English is my first language and I'm horrible with it.

At least you have to good things to look at

You really suck at being a boyfriend then...i dated an identical twin but after a few months could tell her apart from her sister and identify her voice. YDI

I'm sorry, what? I got lost in #1's picture... So dreamy...