How about making Valentine’s all about her, with nothing for you in the deal?
If you are thinking, “that is what it is already” then maybe you should stop fighting it and go for it. Will she notice? Will she care? Maybe, maybe not. Could you feel better about yourself? Very likely.
So what does making it all about her look like? I have no idea, she is not my wife! You probably have a good idea, and if you do not you can narrow it down by asking, “Which would you rather have” questions. Alternatively, just ask her to tell you her idea of a perfect Valentine’s, and if you think she gives an honest answer, work to give her that (within reason and budget).
What about sex? Glad you asked. Tell her, at least a day before, you do not expect sex. Tell her to just relax and enjoy the day without any pressure of sex. If she likes sex, she might ask you, and then you would have to do it, since it is all about her. If you think she is making guilt induced offer of pity sex, say “that’s not necessary” at least once. If she presses it, take her at her word.
Up for a huge sacrifice? Give her a full body massage – and remind her that this is all about her, and you are not expecting sex. Tell her to relax, enjoy, and pay no attention to the little man behind the curtain.