Those looking for breeding plots with emotional substance should probably start with R. Lee Smith's 'The Last Hour of Gann'. It gets shelved as sci-fi erotica a lot, but the breeding element is so tied to the survival narrative and the agonizingly slow build of trust between the human woman and the lizard-like alien. It’s not romantic in a traditional sense at all—more about two beings from utterly different worlds forging a bond out of desperation and need, with procreation becoming this terrifying, inevitable consequence of that bond. The desire feels less like lust and more like a biological and emotional imperative woven into the fabric of their relationship.
Another one that nailed the emotional connection for me was 'Baby & the Late Night Howlers' by Kathryn Moon. It’s omegaverse, so the breeding drive is built into the universe's mechanics, but the focus is really on the pack dynamics and the FMC’s journey from isolation to belonging. The heat cycles and knotting aren't just spicy scenes; they're portrayed as vulnerable, intimate moments where the characters' emotional walls come down. It made the physical acts feel earned, not just inserted for shock value or titillation.
Sometimes the best emotional connections in these stories come from the tension of a situation being morally fraught or logistically complicated, rather than from sweet romance. That’s where I find the depth.