Bad sex life?

Asides from our other relationship problems, I have the worst sex life ever. Weve been together for going on two years and talk about getting married seriously. But i dont know if i can if our sex life is this bad. We have sex 2-3 times a day (yes its a lot) and i tell him to go down on me and how to do it etc but nothings changed. I dont know what to do. I started being more selfish and gave him fewer oral and everything but he still obviously finishes and i dont. I dont want to count on myself for pleasure the rest of my life and i dont cheat; what do i do?