It's not very surprising.
Because he knew that President Gu got married, four months ago, and the partner was that young nobleman from the Quan Family in Yanjing.
However, in these four months of marriage, Dao An hadn't seen President Gu have any contact with the Quan Family. He also knew that the marriage between the Quan Family and President Gu was supposed to be just a business alliance. But what broke Dao An's assumption was that this business marriage was not publicized.
Since it's a non-public marriage, it doesn't count as a business alliance.
Dao An couldn't figure out what Gu Yuan was planning or scheming. He also guessed that maybe it was a fling that resulted in Suisui, and the Quan Family only arranged this marriage three years after finding out.
No one didn't know that Young Master Quan was naturally flirtatious and wouldn't be bound by a marriage.
