He most certainly did use them to get what he wanted when a mission was involved. Do you really think he "loved" Drusilla in Bread and Circuses?
No, he definitely had sex with her, and likely because he wanted to. I don't think he loved her, but I also don't think he was just using her as a means to an end. As for when a mission is involved, I don't think that counts, as his goal is to resolve a mission that means life or death for his crew or the Federation in general. It's why I think "womanizer" is too harsh a term for Kirk, because I don't think he saw them merely as objects to satisfy his sexual desire. He loved women, as Jonas
said. Definitely promiscuous, though, and I have no problem with that.