It's not explicitly stated, but the implication here is that Camille and Thérèse may not have consummated their marriage. After all, nothing about them seems to change the next morning, perhaps subtly indicating that they didn’t have sex on their wedding night. The fact that Thérèse’s expression is described as “frighteningly calm” supports the idea that they didn’t have sex, since she would most likely be somewhat disturbed by having done such a thing with Camille, whom she clearly does not find attractive. Furthermore, the term “frighteningly calm” hints that there’s a certain sinister aspect to her tranquility, as if her composure is really just hiding deeper, more unnerving feelings.