rip at the bottom of her lip

well i was having sex wit my partner last nite of 9 months, and after about ten mayb 15 min i let my wad go deep inside her and as i pull out i see a nice cream pie mixed with blood. apon more inspection she has a nice lil cut at the bottom of her labia or (lips) im 8.5 in by 6.2c and we always use lube and have had sex for over an hour and half (breaks inbetween) has this happen to anyone else or just think is a freak occurrance?

This used to happen to an ex-girlfriend of mine pretty often. Usually if we were in a position where her legs were spread pretty wide, like if she had her legs o my shoulders. We tried a bunch of different things but wound up working best was switching to a longer lasting lube, like Eros Bodyglide.