Attitude is everything. It is a major factor in your wife's libido level. If you have a loving attitude, you will get far. If you have a selfish or self centered attitude, she'll withdraw.
What do I mean by attitude? I mean not only how you perceive things, but how you act and react to things. Your reactions are a mirror of your true attitude. For example: if your wife asks you to get out of bed to get her something and you sigh heavily and say "sure, hunny," she's going to feel you are put out. BUT – if she sighs that she forgot something and starts to get up and you get up first and say, "don't worry, hunny, I'll get it for you," she's going to feel really appreciative, taken care of and loved.
On one hand, you have to get up and will come back to a semi-warm thank you – on the other hand, you will have to get up and will come back to a loving kiss (and a deposit into her emotional libido tank). Either way you have to get up. Which way do you want to do it?
So let go of yourself. You are a man – and you take care of your wife. Trust me: she will take care of you when she sees your attitude of love. When she feels loved and safe and taken care of – when she knows in her heart that you would do anything for her – her libido will be on the rise and you will reap what you have sown.