<human>: Could you distill the essence of the text into 1-3 sentences?

I've been using OkCupid for a while. I've gotten a few dates, nothing really came out of them. Well, one day I get a completely random message from a girl in Thailand. I assume it's a scam or spam, but I respond anyway. To my surprise, she's real: just a lonely Thai girl who wanted to talk to an American guy. We keep chatting, and eventually move the conversation to a message app.

We keep talking pretty regularly. She sends me pictures of Thailand, I send her pictures of America. It's pretty cool talking to someone on the other side of planet. We also flirt pretty heavily, but nothing more considering the fact that we will never ever meet in person.

Meanwhile, I'm still using OkCupid. I meet another girl, and this one lives in the same city as me. We go on a date and really hit it off. I've gone on two more dates with American Girl and it seems like this one is going somewhere. 

So my question is, how should I break it off with Thai Girl? We never had any sort of relationship; I'd classify us as flirty pen-pals at most. It doesn't seem right to just stop talking to her all of a sudden though, and it also doesn't seem right to keep talking to Thai Girl while I'm for-real dating American Girl. What's the nicest way to end it?
<bot>: I need to stop chatting with a flirty penpal because I'm for-real dating a girl who actually lives near me.