Relationships and consequences

I think they overcorrected in TS4 since in TS3 it could be too extreme for Sims to run halfway across the open world and accuse the other of cheating when nobody had witnessed it. I've had stories where it fit the story beautifully that the oblivious husband had no idea the child wasn't his, so I wouldn't necessarily want him to automatically know just because she's pregnant. But I agree with you that there aren't enough consequences for when the spouse does find out the other is cheating.

The fact that you are playing with free will off might exacerbate the problem, though. She can't autonomously confront her husband if autonomy isn't on.

I don't have a problem with spouses not caring about seeing cheating in my game - they seem to care a reasonable amount. But what does bother me is that the kids have no reaction. TS2 was too extreme in that the kids ended up hating their parents after a split because they'd get upset at their divorced parents for "cheating" every time they flirted with their new partner. But in TS4 there's just no long-term consequences. It was really moving to see children and even toddlers getting upset in TS2. The lack of a functional memories system in TS4 is a big part of this flaw.