Tame the Tantrums!
Address the issue at its source. If there is peace between the adult members of the family, your child will be more at ease and manageable. Domestic quarrels tend to frighten the child. They may think that they are to be blamed for the quarrels, and become angry with themselves and others.
If this is not the case see if there is any physical difficulty or discomfort which is troubling them. If even that is not the reason, it is just that they are used to getting their own way by throwing a tantrum. You have to make a distinct change in the way you handle your child’s tantrums, now that they are older. Be firm and make it clear that this behavior is no longer acceptable at their age.