It’s good that you understand that having casual sex is not in your best interest. What you need to find is a permanent partner who will love you, and then sex will be a part of that relationship and you won’t be used. In order to make sure that a potential partner is not seeing you only for the sex, you have to hold back. You have to keep from having sex until you are sure that the relationship is real and that the two of you really do love one another. Now I understand the temptation of going all the way on a first date because you become very aroused. And that’s especially true if you’re not a virgin, as the desire to maintain one’s virginity is a good braking mechanism. The solution I offer you to this dilemma is masturbation. If you relieve the sexual tensions by masturbating; more importantly if you know that after you say goodnight to this person you can relieve those tensions via masturbation, then you can develop the strength to say no. Then when you enter into an emotional relationship where sex is appropriate, you can give into those desires to have sex with your partner and no longer have to masturbate. So dig down deep and find the strength to resist casual sex and in the long run you’ll be much happier.