What am I doing wrong?

EVERY SINGLE GUY I’ve been with just wants me for sex. To USE me for sex. I just meet this sweet amazing guy (or what I thought was) we hung out, even had a little kiss. I told him upfront I’m not having sex with you right now. He said that was fine with him but the next day he asked for nudes. I texted him back and said “are you being serious” and all he said was “lol” . Im literally crying as I type this because it doesn’t matter how sweet & nice the guy seems he always just wants sex. What am I doing wrong??