It's wrong to assume someone is lying without proof
Jan is upset about her partner coming home late and giving a questionable excuse.
Jan wants to confront her partner.
Jan brings it up later and decides to trust her partner until given more reason not to.
Jan confronts her partner and doesn't believe a word he says.
Jan's partner appreciates her understanding and being able to move past it.
Jan's partner is upset because of her lack of trust.