the father of my girlfriend loves to watch when we are having sex – is this normal

i have a serious issue, when i want to get laid with my girlfriend, her father allways insists to watch it when we are doing it. He says he has to observe that imnot hurting his daughter.hes a chief medical officer and some of my friends told me, that those guys behave strange when it comes to their daughters. Anyway, for compensation he allways pays my dinners with her.i think its fair but strange deal