Take a look at this:

The husband should fulfill his marital duty to his wife, and likewise the wife to her husband. The wife's body does not belong to her alone but also to her husband. In the same way, the husband's body does not belong to him alone but also to his wife. Do not deprive each other...  ... so that Satan will not tempt you because of your lack of self-control. 
~ 1 Corinthians 7:1-5

Basically, within reason, it is your marital duty to satisfy your wife and her duty to satisfy you.  If you and she are not satisfied, then others are more likely to tempt you or her away from the other and into an affair.  Good advice from a good source.  But with a poor libido and no passion, this scenario will not happen.

So - can you point to this passage and say: "hey, even the Bible says not to withhold sex from me"?  Can you demand intimacy?  No.  Demands and guilt trips will only make it worse.  Pushing a woman does no good at all - you probably have experienced this.  If you want her to resent you and ultimately be repulsed by you, then go ahead and try to "force" sex on her.

Men are easy: a nightie and a sexy look is all it takes.  Women need much more - they need to feel loved unconditionally.  It is only then that her libido and passion will rekindle.  This means you need to change your mindset. 

This is the first step.  The mindset you need is that of a loving husband who serves his wife and does not expect sex as a reward for what he does.  You would be amazed at how taking the pressure off can yield results.  So get ready to go without for a little while - if you have children, you have done this before when you had to wait six weeks after a birth to have sex again.  Get ready to do it now - why?  Because she has to trust you - she has to see that you have no expectation and believe it.  She will believe it because it will be true.  Anything worth having is worth waiting for.

Now I am sure that some men will hit the back button right away, but trust me: this will work (barring any serious dysfunction).  And you will probably not have to wait too long when you start applying the steps you will see here.  Give it a chance - you will be glad you did.