Me and my husband want to have but we just don't. how can we change this?

We work different shifts, we have two children (4&6). When he gets home I go to work When i get home he is in the bed. on the weekends i work the most part. I feel like we don't have time for the pion and romance we had before we got married. we use to have fun when we had now it is just a chore to find the time and energy to have it. we both work demanding jobs and have two nosey children that if we disappered they come looking for us. the kids get up early on the weekends. we are scared to lock our bedroom door because our rooms are upstairs that they may go outside if the can't find us. when we do have i want that pion and romance and it has to be so quick before the children find us that i don't enjoy it.Help e find a way to get that pion and romance that we miss sooooooooooo much. The love that we feel for each other is there the isn't. Help!!!!!!!!!