I'm going to break up with my girlfriend days before valentine's day and our second aniversary
Why do you want to break up with her?
I feel I would be happier if I do this.
You don't have to stay in a relationship that doesn't make you happy, but you shouldn't do it before such important milestones in your relationship. Why don't you make these days the last couple happy days of your relationship? Both of you deserve nice memories to carry on after breaking up, not anguish and despair around these holidays.
I don't care.
Even if you are done you should break up respectfully. It is wrong to keep stringing someone along if you no longer want to invest in the relationship.