Alpha and Omega have a very high compatibility rate for their pheromones (95 or 100% I think). But ML forces MC to undergo gland replacement (and also abortion I think, although that didn't happen). Then their compatibility drops to 8%. Then starts ML's grovel to get back the MC and their child. ML's assistant is a beta and resigns to move along with MC when MC gives up on the ML. They rent an alpha's in and the novel hinted at this alpha being paired to the assistant. Then there is a younger alpha around the MC but the MC thinks he doesn't deserve him.