First of all, it does not sit well if a Stepparent marches in, takes over the discipline, declaring or insinuating the parent has been way too lenient. It is better if discipline of one’s own children stays with the biological parent for at least the first couple of years of the remarriage. If not, the anger a child/children may feel at this intrusion may encompass a child’s life and remain for many years even into adulthood. This can lead to rebelliousness and acting out as the child/adolescent feels ganged up on by 2 adults and wonders why Mom(or Dad) doesn’t take their side.