going down town

So me and my husband have been together for several years. When we first got together he would go down on me when I wanted him to. Then I got pregnant with our daughter and he completely stopped during the pregnancy and he has done it maybe 3 times since she was born and she's 5 now! I've tried asking him why he stopped but I never get a strait answer. Uhg!  How do I get him to want to again?!