Both
In the beginning they show he Isekaied into a novel he read with the main characters having his and his best friends name. Later on they show that mc receives therapy and sees some memories of the og mc(novel) that aren't supposed to be there. They also show mls pov in later chapter when he starts acting kinder and more similar to mcs friend that the world from which mc Isekaied was actually not real and was just a fake world that the real huimin created as a means of escape kinda like a dying wish or something where there were no alphas or omegas just humans and he and ml were simply friends. So a bunch of things happens and mc finds a safe in mls office containing pictures related to his world like his family and stuff leading to him confronting ml and running away. You can read the chapters and see how it al unfolds. Personally I really loved the story because of the character development and plot.
Great Plot twists!!! Also super spoilers ahead. Definitely recommend sorting down and reading the whole thing.
The world shown in the first chapters was actually NOT the real world. It was a world made by the MC. He has emotions and imagination brought about by the fact that he felt miserable with his current life, his relationship with his husband and eventually fueled by the lost/miscarriaged of their first child. He created the false world where the world was not biased, alpha-beta-omegas did not exist, he had 3 sisters and his husband was just his kind best friend. Further plot twist, his best friend was the same literal guy who was also isekai-ed because he wanted to save MC. (Great story IMHO, the way how the author describes the fake world and parts the husband wanted to change for MC was astounding .)
Apparently the real world was the one he awoken to, the one with alpha-omega. MC memory did not really came back. Instead, he found out inside a safe kept by the husband were some old familiar drawings drawn by the MC. His husband revealed to MC that the world he made was perfect but fake, and he drew them to escape from their world, the suffering and the miscarriage.
MC accepted all side of the stories both the fake world and the IRL. A lot of happy parts here happen And they lived happy ever after, married
I remember that mc isekaid into some omegaverae book with his bsf as alpha so can anyone explain was that really that case or he just got amnesia type shit