i need help understanding something.

my boyfriend was checking his e-mail and i was sitting beside him, we were looking for apartments. he uses g-mail and there you can see the beginning of the message. and one message begun: "good! you will increase your fun! don't forget i'm also your fun" - the message is most likely from some japanese girl.. therefore the tacky english..

i know he has female friends from the far east.. he said when he was in japan he had some mutual crushes there but nothing serious. he's very into japanese/korean culture, i understand if he wants to be in touch with people from over there.

and i don't care if they swoon over him just as long as he is committed to me and doesn't do anything about it. he's not really acting suspiciously.. he still holds my hand everywhere we go, takes me to see his friends, takes me to see his parents, grandparents.. (we did that last week - i saw the message at his dad's house - his parents are divorced) and when i was on the train back home, he sent me a txt saying "i'm happy you're in my life".

my friend said he seems genuine enough.. but am i naive or over-reacting? is saying "don't forget i'm your fun too" just a friendly saying over there in japan? or korea. or maybe she didn't really know what she was saying?

there just doesn't seem to be any sense in it if there is something going on between them... why the heck does he want me to move in with him if i bore him? he surely can't save money up for a trip to japan when he lives with me.. crazy..

please somebody help..