I need help..

My boyfriend always asks for nudes. I always give them to him because I don’t want to upset him. I never want to. I just want to feel loved. But recently he asked me for some when I needed to be comforted after something bad happened. I snapped at him and he got angry with me. I told him that I feel like I’m just being used for pleasure and that I feel like I have no worth. He played the victim saying that it was a one time thing (which is not true) and I don’t know what to do. Please help