Husband not turned on anymore?

We have two kids ages 7 and 10 months but our sex life has been great. We we're having sex multiple times a week and on a bad week we'd only have sex once a week but it was still great. He has always gone down on me before sex and sometimes he eats my booty as well lmao TMI! But a couple of nights ago he wasn't even interested in doing anything to get me wet he said, "I'll just put gel down there." And his penis wasn't even hard or getting hard for nothing. So finally it did get hard and we had sex I got on top and he got off but I didn't. It was boring and not what we have been doing. Then last night he went down on me but his penis for hard for a minute then it wasn't hard anymore and we didn't even have sex because of it. I'm getting frustrated! BTW I'm 24 and he's 27.