I cheated on my boyfriend, denyied it. Now he wants a polygraph test.. (read more about the relationship)?

I cheated on my boyfriend last June at prom, with the guy I went with. It all started when my boyfriend started asking if I had danced with him in reality I did and we had also juked acouple songs. (But I kept denying and said we only danced something else) so my bf took my phone and pretended to be me texting my friends. That's when one of them spilled and said that me and my date had also kissed 2 X's. He then confronted me about it and I kept deny deny deny. I would start spilling the truth slowly as I started getting caught up more and more. I told him that was it, but he feels there's more. The whole truth is out nothing else besides the dancing and 2 pecks. But he says he thinks I had sex with him. I told him I wouldn't go that far, I lost it to my bf the kiss was wrong and it the BIGGEST regret I've made up for it by leaving ALL my friends, getting his initial tatted, and I haven't done anything behind his back. He says he wants a polygraph test($450), of which I have to pay if I want this relationship. Till this day he calls me names "busty" when he gets mad. He says I have no voice, I should be shitting bricks because he hasn't found anyone. And this relationship has turned emotionally abusive, he curses me out makes threats ect. He also says it might take many months/years before he can trust me. So I asked him when these results come back when would I start gaining trust, and is he going to stop treating me that way? Because if things aren't going to change I can't take the test. He said I'm a bullshitter,and he wants answers first before he can decide. I said I'm not gonna waste my money on a relationship if its not gonna last. Am I wrong?