I just bought ex-b a book I know he'll love - I'll give that to him and a not-too-romantic type card. Maybe a large bar of his favorite chocolate too.
I think the most important thing is to get something your W will love, period. She may not be wanting stuff like flowers now, but something for her well-being (like a spa gift certificate) or a book you know she'll enjoy...something that doesn't expect anything on your part, and nothing that puts pressure on her.
