Okay... here's an example scenario:
The girl says to the guy... after weeks and weeks of dating, "I only want to have sex with 'someone I love,' and your not quite there yet, it takes time."
Now... in this situation... I think that the guy should be entitled to go off and cheat.

Because I think sex is like a 'reward' for the hard earned efforts of the guy showering her with gifts... and I think refusal of sex is like a punch in the guys face, and will cause a failure in the relationship.
Nothing worse than going without sex.. knowing that you're in a relationship with someone. The girl is basically just on a power trip.
Like Billy Connelly once said...
"Girls need to feel loved to have sex... but guys need sex to feel loved." --------------------------------------------------------------------------------
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and Donald, Billy Connolly was spot on.
maybe this girl sees you as having potential as a long term partner and is testing you, which is no good to you right now, of course ,as you need sex.Maybe you both see your coupling as having different outcomes.
She may be in it for the long haul, women can decide very early on if your 'right' or not, its instinctive.
A note to you, females dont subscribe to the veiw that if a guy spends money on her or not, neccessarly entiltes him to receive a payoff. It cause her to feel as though she is being paid for, and there is no loving intent behind this scenario.Its actually insulting to some women.
If a women is so devasteted by your sexiness and charm , a sexy ,wicked smile will do the trick and wont cost you a cent. It IS subjective as I said..
She is waiting for a depth of feeling to evolve as she obviously needs this to make her first 'encounter ' with you special and memorable. Trust her on this. It means she has a high regard for you and the resultant first sexual encounter wont be a disappointment, thats for sure, unless she is a virgin, in which case this would,nt be her fault.
Donald, you must like this girl for you to have spent money and time with her , but if Im wrong and you want a girl to be more in tune with your needs than her own, then you may have to find a girl who is more willing and who's standards are not as high. You are a man you have needs ..find a girl more in tune with you ..
She will develop feelings for you that will result in intimacy, she knows this, but wants the time to be right.
Its depends on if YOU are willing to do the 'hard yards' and be patient. You know your limits.If after more time has lapsed and you have resolved nothing-she may be playing with you and you may need decide if you want to go on with it.
Good luck Donald, its a very frustrating situation and I hope it works out soon.
Cheers.