Losing Virginity

I'm a virgin and I'm worried about losing my virginity. I'm really thin and I know I'm tight down there (I can't even fit 2 fingers in comfortably), and my boyfriend is pretty well endowed (like 6-6.5" and pretty big around). We aren't really planning on taking the things to the next step anytime soon, but I'm wondering if there's anything we could do to make the first time not hurt so badly? I know that there will be some pain from the hymen breaking but I'm nervous that he just won't fit at all or it will hurt too badly, or even that I might tear a little. He's worried about hurting me too, and we've talked about the size problem some. Any advice?