Moon by Wendy Rathbone

In a beta-ruled world where the betas are sterile and population growth is at stake, the breeding of alphas and omegas is strictly controlled.

Alphas, considered dangerous and aggressive, comprise only five percent of the population and are kept isolated from the public. Omegas comprise only fifteen percent of the population, and are required to enter breeding programs at age eighteen.
Moon lives in a locked cell where his alpha emissions are monitored, forcibly collected and stored.
Kaydi is an omega whose fated future is to live on a pension in a government subsidized apartment and, through artificial insemination, gestate as many fetuses to full-term as his body permits before he is too old to carry on that task. He is not allowed to marry. He is not allowed to keep his babies.

When both men are chosen to participate in a new beta-approved program of arranged marriage and a forced family unit, they are thrown together into close living quarters as utter strangers to each other.
With Kaydi about to go into heat, the two face conflicts involving their duty to society, lack of freedom in a controlled environment, and compatibility issues.

Non-shifter omegaverse mm romance.