Responses
The marriage was just a lie made by his father to get ML to come to the palace.
ML is not the type to 1 step back 2 step forward like his father.
So even though the emperor summoned ML, ML still doesn't want to come.
Father don't want to aggravate the emperor, so he sent that letter lying about Robel getting married to get ML to come back to the capital.

7 years? That's a lot, and marriage?