Really? So if someone is worried when their SO doesn’t come home or answer texts and drives around looking for them, that is “guilty knowledge”? And your justification is because you never worry when your SO stays out all night? How does that make any sense.
I promise there are a lot of people both male and female who have been worried about an SO under similar circumstances and no murder was committed. In fact, the opposite is very common. Someone goes missing, the SO never reports it, worries or looks for their SO. That is the situation that typically plays out when someone has murdered their SO. jMO.