Not an excuse but

I thought maybe in this timeline he was forced.

Still ass move to put the blame in the Person totally in your control

I get what your saying. Something seems incredibly off, like maybe Sejin's adopted father fed Ido some stories . Whatever it is, it ain't good...

But that wouldn't make sense as the father needs Sejin to succed and that would be easier If Ido trusted His son

No, he was just sexist scum for omegas( like some men thinks that all women are golddiggers). He agreed to marry Sejin to stop with all marraige proposals and to takeover company of Sejin's family.

Interesting, is that in the novel?

True, but the only reason I drew that conclusion was because Ido thinks he's a slut from his comment, This is all speculation on my part though :)

Yes, in specials we get Ido's POV

Thanks :)