The reason you got married was simple. Azar wanted to control him, so he looked for someone who seemed easy to manipulate so that they would inform him. That's how they chose you.
What really happened was that you formed an alliance with Alhaitham on the same day of the wedding. You would pretend while in reality you gave him all the freedom he needed. And after saving Sumeru, your marriage was no longer necessary, that's why you brought up the subject, considering invalidating the marriage between the two of you.
He had asked you for 6 more months without giving details, he only said he would make sure he achieved what he needed in that time.
You didn't know that even if it was him who said there would be no rapprochement and that he would never love you, he was actually interested and wanted to keep you by his side. His problem was that he wouldn't admit it out loud and it was hard to make you fall in love after that. You were too elusive.
The money he gave you was only used for household expenses, never for yourself. If he started a conversation, you gave a simple answer that cut him off. In the shared room you continued using the sofa so as not to sleep in the same bed. You even admitted out loud that you would look for a real marriage after the divorce when he asked you.
He thought about asking Kaveh since you got along well with him, but his pride was more than asking his friend.
He couldn't just leave things as they were. He went to try to talk to you again when he saw you secretly eating something sweet in the kitchen.
"...What are you doing" asks your husband, seeing how you looked like a squirrel crouching next to a closet.