It's only natural that Alphas and Omegas love each other. Alphas are naturally attracted to Omegas, and their world is full of poems, songs, novels, etc. in which Alphas and Omegas promise each other eternal love.

...So, it's impossible for an Alpha and a Beta to love each other in the first place. Where in the world would there be such a crazy Alpha? After being revealed as an Alpha, Gunwoo realizes that he likes Junghyun, a Beta, and tells him how he feels, but Junghyun rejects him, saying, "That can't be true. You're an Alpha, and I'm a Beta."