Pain during doggy style

Okay, my boyfriend and i have been together for almost 3 years and we recently started having sex. Its mindblowing and amazing but he's huge. Thick and long and it hurts at first but it goes away and im fine but when we do doggy style it just hurts. Theres only pain. Where ever he's touching in me it just hurts. Any tips or maybe explanations as to why and how to prevent? I also have close hip bones which might be a fault. Thanks!