If you're speaking about the time he interviews his wife while still in disguise after arriving home to Ithaca, we learn that he is a smart, wily hero. He doesn't know what his wife as been up to all the years he was away at war and the years he spent trying to get home. He doesn't know if she still loves him, or if she's been unfaithful to him with any of the multitudes of suitors that have taken over his house in his absence. He must first test her to see if she has been a faithful wife to him all these years and if she still loves him. He wants to know if he has something worth fighting for. If he's going to fight to get his kingdom back, he wants to know if there's something to be fighting for.