That is a lovely suggestion Peter :)
Might be an idea to have a few different things on so they can pick and choose, for example some who might have recently lost partners might not be on for the romance side of things.
When I used to volunteer at a local hospice and a residential centre for the disabled, I used to help with diversional therapy and organising entertainment and we would have a couple of things on and there would be things available for people who didn't want to do group stuff.
You could use the love idea but more generally, people could talk about loved ones in general be it a partner (living or lost, even a past love), children, pet even. Basically just talk about the love or loves of their life, makes it a little more inclusive.
Maybe a teadance element with old romantic songs - the more mobile could have a bit of a dance, even if assisted or just sway along in a chair. You could even see if you could show a good old fashioned romantic (or feelgood) movie or even a nostalgic programme about life back then, the stars etc... Even make it like an old fashioned trip to the pictures with the lights down (maybe drapes up) and old fashioned tellers serving icecream etc... (bear with me, I'm only 32 so not sure what it was like then!).
I like the idea of valentine cocktails too :) The liqueur trolley was always a big hit at the hospice :)