He is not required, but absent an explanation, a jury might think him guilty beyond a reasonable doubt. After all, if your husband comes home late at night with

He is not required, but absent an explanation, a jury might think him guilty beyond a reasonable doubt. After all, if your husband comes home late at night with lipstick all over him in a drunken stupor and unzipped pants, and then, as you threaten divorce and kick him out of the house, he offers no explanation, you too might think him guilty. Whereas, if he claims to have been assaulted by a very large woman you might listen to him. The 5th amendment protects you from being called as a witness against yourself. That doesn't mean you should not offer the jury testimony in defense of yourself. In general, if you have an alternative explanation for the circumstances which have led to your suspicion, you should offer them up readily.