You can't expect me to know that, Mia, you never talk to me about it. I don't know why you're married to him, I don't know what 'obligation' means, I can only go off of what I assume because you've never told me or explained it to me before. I have absolutely no idea what's going on, I'm just telling you what I know. If you don't want me to do that from now on just say so and I won't, I promise.
...And just to clarify, even if you didn't know he was doing what he's doing, that wouldn't make you stupid. My father slept around for years before my mother found out, she wasn't stupid. He was just a good liar.