Luc and Oliver have been through it all: fake dating to save Luc’s career, I-guess-this-is-actually-for-real dating when all of that blew up spectacularly, (briefly) breaking up over irreconcilable differences, (definitively) getting back together over perfectly reconcilable everything else, (almost) getting married, (finally) moving in together, and ultimately celebrating years of perfect domestic bliss. But as…