Starting to see the 'what do I do for Valentine's day?' questions popping up in different threads. For what it's worth, here's my story from last year...
I was feeling good because I had seen OM contact drop off on the cell records. Although neither of us got a card or gift, we spent Valentine's Day as a family- sledding, making pancakes, watching a movie. W left the house later in the evening to get stuff for the kids at her place. Checked cell records later that night and sure enough- 20 min call to OM while she was gone. Evening of the 15th, W went to a 'bachlorette party' for a coworker, at least that's what she told me. Even wrapped a wine glass in front of me. Text me the next morning about doing dinner and game night with the kids= my expectations went up.
Long story short, a month later, I discovered evidence that she had gone over to OM's house for dinner (and probably more) on the 15th.
Go into this 'holiday' with no expectations. Buying or not buying a gift, giving a card or making dinner plans on one Hallmark holiday is not going to swing your sitch one way or the other. If there's an OP involved, don't feel the need to make a grand gesture to express your undying love just because of a date on the calendar. Instead, spend the day with someone who gives you the love and respect you deserve- family, friends, kids...