He is obsessed by body fat

I have struggled with my weight all my life. Always excercised and dietted and my weight is always yo-yoing. To the extremes. At some points I have been as large as size 26 and others as low as size 10-12. At the moment Im somwhere in between. however this post isnt about me. Its about my new partner. He is incredible. He has the most awesome and athletic healthy vegetarian body I have ever seen. He is clean and tanned and looks like he just stepped out of a male clothing catalogue. Better Even! 8) So I am so blessed to have such a fabulous physique in my hands. Now the problem i have is this. He has the most biggest apendage I have ever come across in my life. HUGE. He likes my fat body, he has even suggested that he would not be dissappointed if I was to even gain more weight [ I wont be doing this for anyone] The problem I am having is when we are having sex.. And that is quite often and several times a night. He gets to a point where he wants to dominate. He will go slow and then suddenly 'thump' [thats the best term to describe the force and sudden jolt] me. I would say his penis is around 10 inches long. Is it at all possible, it does feel it at times, like the tip of his penis could be entering my cervix. Im a 32 year old woman, I have had one child 7 years ago. Is it possible? I enjoy this painful sensation during sex. I have searched forums and there are fools suggesting that its the g-spot and other ridiculous things such as bruising. I'm tellin you, I am certain that he is entering the cervix, he even suggests that there is something up there that grabs him when he pushes into me that hard. Please let me know if this is or is not at all physically possible. And if so, could it cause any future complications with conception or childbirth if we continue with this practice