Hello and wel cum Paul, if after 15 1/2 years she can only get 3/4 of you then there is not much more to be said. That in itself is still a great deal, what has made her stop there? is it the pain from the size? the length? I am sure that you have tried all the different positions. Short of just slamming it home and just leave it there for a few minutes I am at a lost, myself I am 5'1" and 115 38-28 35 and my husband (when he could) was 6" and several years ago after the nest was clear and he got prostate cancer and began treatment we would fuck 2-4 times a day 4-5 days a week. Now he cannot get hard but his tonged has gotten longer and thicker and he has plenty of toys , we started a openness and ne not enjoys me fucking other men(cuckold) and in a few of our gathering there is one genital that we call the horse man , soft he lays out at 11" but hard he will top close to 14" and when he starts to fuck you it takes some time to get that monster worked in then rest before he starts the plowing and plowing he will do for sometime, after it is hard to walk and my little box is so stretched out but give it a day and m husband says we are back in the saddle. I hope this helps you out a bit