This Sweet Sickness (1977)

David is an accountant. He leaves town every Friday, pretending he is going to take care of his parents at their old people's home. But actually his parents are dead, and he spends the week-ends converting a chalet. He intends to live there with Lise, a woman he knows and loves since childhood. But Lise has just married another and has a baby. David's mad love does not see those facts as an obstacle...