Boyfriend won't let me see his facebook page?

[Primera]

I've been in a 1 and 1/2 year relationship with a Muslim man. We're both the same age (mid-20s) and have had a very positive relationship thus far. In the beginning of our relationship, he kept reiterating how FB causes problems and that he didn't have one. Several months later, when I came back from out of town...I saw a page on his computer screen when he was at my house...and it appears he had an active profile that he uses to browse other girls..plus those "rate me" websites as well. He claimed it was his brother (hmmmm...) and though I let it pass, I never forgot it.

Recently, he mentioned something about his facebook. And I figured after almost 2 years of being together, I'd friend him on there. His response has been "he doesn't know how to even use it" and that he doesn't even go on it, it means nothing to him. Finally, the other night he told me "fine u wanna be my girl on facebook? then we'll keep it virtual and u won't be my girl in real life"...i thought that was a hell of a response.

Given the circumstances of his Religion...we don't have a normal relationship. Since Muslims cannot date...his family knows nothing about me, he's spent only one night over at my house, and truth be told, i feel like he knows more about me then i know about him. it's like i cant even ask about his family....i know he still lives with them, and i highly doubt he has a wife living with him as well because we actually plan falling asleep on the phone together several nights out the week. which would be kinda impossible if he had someone living with him...

I know many people will be quick to scream "harem" at me for dating a Muslim, but know this...he's mixed British and according to him, his family would let him date who he wants. All i want is people's opinions on this situation with him not letting me even see his facebook.

I have a profile myself and I told him not only would i let him see it...he could have my login/password if he wanted. and when i ask him why he won't reciprocate and just let me see it...he says 'he's done with me" or "f*** me and facebook" or "im giving him a headache"....responses like that make me feel like he's flirting around or even chatting with potential brides on there (at the end of the day, im no fool...perhaps he really wants a Muslim woman in the long run)

any advice would be appreciated, thank you
***Thank you all for these answers. I've definitely been foolish, and honestly im glad he never actually spent the night over...makes it easier to cut the emotional ties.

*According to HIM, British Muslims are not as strict with dating guidelines...given that there was some allowance for a non-Muslim to marry into the family at some point? yet he has told me that his family would prefer him to stick with a Muslima.

Ah well, I live in the Big Apple...I'll get over it.

Thanks again everyone..champagne kisses!