Let's switch women! My dick is a lot shorter than yours and not quite as thick. My wife's vagina is infinitely deep. At 60, I think I'd like younger too!
Seriously, though, it seems to me she has an arousal/lubrication problem primarily. However, your big cock may be making it more difficult to over-come due to fear of pain. You might look for Zane Blue's posts on how diet can alter female sexual response. With better response and lubrication on her side and care to avoid hurting her, things could get better. On the other hand, it seems a waste of an outstanding big cock when there are so many big understimulated pussies out there.
Since I've been married and loyal, I'd forgotten about how some women hold their legs close together to avoid too much penetration. I remember telling one. . . "uh, you don't really have to do that with my cock. . . Its already all the way in. . ." She finally relaxed and smiled with relief, but soon it became clear she could have used a bigger one. . .!
