Is it wrong to lie this drastically to a woman?

Here's the deal. I've been seeing this girl really only because I wanted to have sex with her. I have no desire to have any kind of relationship with her. I have been with 5 girls prior to her. She thinks I suck at sex because I told her I was only with 1 girl before her. The truth is I just wanna screw her and blow my load and be done with her. I have absolutely no desire to look out for her pleasure. If it makes you feel better, she only wants me for sex too. But since I decide when I blow, it's all me.