That the male partner can have baby's and with a love romance. Like Alpha/ Beta/Omega.
Here are few. Hopefully some you haven't read yet.
http://www.mangago.me/read-manga/tadaima_okaeri/
http://www.mangago.me/read-manga/romantic_joutou/
http://www.mangago.me/read-manga/oyasuminasai_no_ato_wa/
Many Mpreg aren't omegaverse. And many omegaverse story have no Mpreg though they can.
http://www.mangago.me/people/tag/2337/Mpreg/
http://data.whicdn.com/images/35843236/tumblr_m11jkpM9xb1r0qnsro1_500_large.jpg
http://www.mangago.me/read-manga/k_no_kouzu/
Thank you so much.
Anytime, dear (●'◡'●)ノ