Trying to rekindle love after 2 kids.. ?

Kat • Pregnant with baby #3
My SO and I have been together on and off for a total of 8 years.. 3 years ago we had our first little girl! Had trouble in our relationship and separated for a few months when she was 6 months old. We got back together and things have been good and we started trying for a second baby when our first turned 2. Now that we have our second little girl I'm still trying to find that spark again. I figured this Valentine's Day I could do something special for us and have a little date night at home once the girls go to sleep. Our second baby is only 3 weeks old so I'm not trying to have a baby sitter yet. I love my SO but I don't feel that spark like we used to have. I was looking back at a picture of when we first started dating and was trying to think of why we fell in love. What are some ways to get that spark back? We are so caught up in the kids and work it's been tough having a relationship.. HELP!