Hardly any sex but don't know why :/

Tiarnee🌱 • 21 years old. 2 beautiful daughters. Baby #3 Due May 2018! From Australia.
My boyfriend & i used to have a long distance relationship. Everytime we would meet up & stay with each other for a week or 2, we would have sex 3 times a day. Now we've been living together since 2014, we are hardly near each other. We have sex once a week & we don't even cuddle, kiss or do anything romantic. Can someone please give me some advice on what to do?! Especially before valentine's day! :(