Nothing, you can do. Valentines Day is just a normal day. You should love your boyfriend every day not just on one day. If he still wants to be in a relationship with you than he'll come back to you. We all need space during a relationship.
First I can only imagine your age, if he was serious about you he wouldn't have said that the last thing I would need is (some space) from my girl, especially in a day like valentine's day... I'm sorry but you should get over that guy, he's not worth it. Spend some time with your family