As the Aladdin went on hunting, He was away from his house when Maghrabi came and took his wife and the palace, so, Aladdin was away from his wife from many days, and we all know, husband and wife is the relation in which, both the husband and wife can't live with out each other.
Now When the Princess saw the Aladdin after so many days, she became emotional and cry with joy. Alladin did the same and met her wife and ask her what happen when he was not around. She told her everything.
Then Aladdin ask her about the Lamp, and I think Aladdin should get angry on the princess, but he listen to her and he know that the princess doesn't know about the magic, he ignored the ignorance of the princess and start thinking about how he can get the lamp back.
We know if he go in front of Maghrabi will use the genie against him, and then he won't be able to do anything. It is the princess who can help the Aladdin to gain the Lamp back, but it will put the princess in danger.
But Alladin couldn't do anything else. so, it was his only chance to catch the maghrabi and got the lamp again. Hopefully everything goes well and Princess will be safe.