Ah, that's what I get for not replaying Rose before this one. Thank you so much for the quick reply!
I've actually just finished his route with the "new life, same love" ending and I wanted to say it's fantastic. I won't spoil it here for anyone yet to play it, but the characterisations and plot were as wonderful as ever. I was playing the route where the MC didn't become Guillaume's queen at the end of Rose, and it was great to see the fallout of the decisions the MC and Frederique made.