This is a pretty obvious, basic economics point, but elementary supply and demand says you should never ever ever go out to dinner someplace nice with your partner on Valentine's Day. The fancy Valentine's Day dinner is a double-whammy. On one hand, demand for such meals surges, which raises prices. Yet sometimes paying peak-demand prices is just what you have to do. There's a reason everyone wants that Caribbean beach vacation in the wintertime. The true problem with the Valentine's Day dinner is that quality is likely to take a dive.
Any restaurant knows it's likely going to be flooded with customers who are extremely unlikely to be repeat business one way or the other. That could be folks who just don't have the financial resources to eat at comparable establishments frequently, or it could be couples with kids and little time to dine out. Either way, it's a special occasion. Which means it doesn't much matter how much your customers like the food. They'll enjoy the rare upscale night out anyway, after all, but probably won't become regulars no matter how much they like it. Meanwhile, they're not going to have a good sense of what the competition churns out on a regular night so won't have a genuine basis for evaluation anyway. You'll likely get a prix fixe dinner composed of the highest-margin possible items at slightly inflated prices, plus a below-average evening in terms of attentiveness to the cooking and the service.
Which isn't to say you shouldn't do something. But do something casual and fun (my wife and I will be getting some Chinese food) and do the fancy dinner some other time.