Cheating is bad regardless of NT/AS distinction. The betrayal of trust is painful for them as well. At your age, it's fairly common though. This is one of the reasons I didn't date much at your age. The temporary physical relationship dynamic has little benefit for me.
If you think girls are after you for physical reasons, then my advice would be the same as it would be for a girl at your age. If you want something more than sex and a fling, don't give them any early in the relationship. Make them wait, and if they're only interested in sex, they won't wait and you can move on without the angst. One caveat to this is that since you're male, you'll have to show your romantic attraction in other ways (kissing, cuddling, gifts). Girls are used to guys being after sex and if the guy doesn't go for it without any explanation as to why, the girl may think he finds her unattractive and/or is friend zoning her. It bears repeating that guys are normally the more aggressive when it comes to dating and deviating from the norm always risks misunderstanding.
If they're after you because of your money, don't spend any on them, and be deliberately cheap, and you will be able to tell pretty quick which ones are really interested in you and not your wallet.
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Self-Diagnosed Dec. 2010
135 Aspie, 65 NT--Aspie Quiz
AQ 40
BAPD--124 aloof, 88 rigid, 83 pragmatic
EQ/SQ--21/78--Extreme systematizing