I really like what J.B. said...I second her sentiments.
Also, I have found that communication is the key.
You need to say what you want..and also ask him what his needs are. Then find ways to meet each other's needs. This should be a conversation that is on going.
I find all too many of my friends are afraid to breech this subject with their husband. That just floors me!! You make babies with him, he has seen you give birth which is not the sexiest of occasions and yet you both can't talk about physical intimacy needs?
I also have found that women talk with eachother about sex but men don't talk to eachother about sex. It can be a lonely place for a man in this department if he has no one to talk to.
I also find that it is important for a wife to initiate with a husband...not have the husband always begging or hinting that he wants to be close. I initiate whether I am "in the mood" or whether I really just want to sit down and get lost in a good book. (which is often)
I try to keep track of our frequency and make sure we are together a few times a week. It isn't about "scheduling" sex..it is about not letting that part of our life get put on the back burner because of the laundry list of to do items. Laundry and dishes will always be there the next day. Events like Boston Marathon..and 9/11...and Texas explosion are example to me that my hubby just might not always be there.
I believe whole heartedly that physical intimacy whether it is a quickie or long lasting hot steamy,rip my clothes off sex is important throughout a marriage. It ebbs and flows in frequency...but should be more flowing than ebbing :)