Making love with my hubby/?

iv gone off /love watever u call it,wats up with me?i want to ravage my hubby but when we get to bed...im dead....i want to but i make excuses,im not a teen ,im 36 wif 5 boys and love it ,but wen it comes to bed i make excuses,am i wrong ,not being rite as i no i aint but help me plz as i want to sattisfie but feel held back......