Sexual assault gone unsolved

Two nights ago a male friend of mine was supposed to give me a ride to work I fell asleep on the couch and made it clear numerous times that I didn't want to engage in sex as I was asleep he had sex w me I woke up to my vagina hurting and he was thrusting in me I pushed him off and ran out I went to the emergency room they completed s rape kit. Last night I went to meet with the detectives and I called him bc they wanted to get a recording of him basically admitting to it but of course he denied it he said that he thought I was awake he says I helped him take my clothes off and I started it bc I touched his penis so the detective tells me that there's no real evidence and it wasn't like he tried to hurt me partners wake their partners up to sex all the time but I made it clear we aren't partners and I said I didn't want to have sex why would I wait til I'm falling asleep to want to have sex