My mom and stepdad got a divorce back in late 2012. It was his decision, she didn't want it. Anyways, that first Valentine's Day (2013) after the divorce, my brother and I took her out to dinner and got her flowers. We continued doing this for three years now. So I'm guessing that's what we'll be doing this year too. We don't want her to feel bad on that day because of the divorce.
But she usually has a great time. She's a strong lady! It also helps my brother and I feel better that we at least have family to celebrate it with. My brother has been hurt in the past by exes as have I once. So it's good to spend it with family.
I wanted to add that Vday doesn't have to be just about romantic love. I think it's a celebration of love in general: God's love for us, our love for Him, family love, friendship love...etc. If you don't have a romantic relationship, it's okay. You can celebrate all the other kinds of love this life has to offer!