Oh my goodness, this whole thing is being blown WAY out of proportion. It's an 18 year-old kid with a crush on an attractive more mature woman buying her a bouquet of flowers and asking her to a High School prom! It's cute and sweet, and if I were here I would be flattered, but think of it as no big deal.
Getting HR involved and calling this sexual harrassment is complete overkill and part of the problem we have today. People have to walk on pins and needles because someone might be offended. Total crap.
However, in a marriage, you have the right to let her know what you think and feel about it. If you are not comfortable with it, then she needs to respect that too. Expecting her to become the Ice Queen at work and only talking professionally is too much to ask, however.
