What is the main conflict in The Blue Afternoon: A Novel by William Boyd?

In 1902 in Manila, the European-educated Dr. Salvador Carriscant practices modern medicine in a hospital dominated by outmoded practices and medical theory. Carriscant's friend and medical associate, Pantaleon Quiroga, also practices modern medicine but is very focused on building a heavier-than-air flying machine such as an airplane. Carriscant is married to Annaliese Leys but their relationship has grown strained and distant. When he accidentally meets the beautiful and forceful Delphine Seiverance, he easily falls completely under her sway. Delphine is married, however, and the social mores of the day prohibit extra-marital affairs and easy divorce.