A/N: All the bits in French come from the amazing song Les Feuilles Mortes ('Autumn Leaves').
La chanson que tu me chantais.
When he kisses Joan - and this is not something he's admitting to anyone, least of all either Martha or Joan, especially as he is having a hard time acknowledging it even to himself - it is Rose he sees standing there, Rose he is kissing, Rose he is in love with beyond reason and misses so desperately.
It's always Rose.
If the kiss conveys a hint of that desperation, he neither notices nor cares. His eyes closed against reality, he buys into the illusion his mind has provided him - and willingly takes a step further on the treacherous road to madness.