It is widely understood that both Tamora and Titus Andronicus are leaders in their own right. When the wars are over, they both have families to return to. So now it is a question of parenting. Who is the better parent? Tamora is a better parent than Titus Andronicus. She cares about her children, she has a good relationship with her children, and she is capable of influencing her children.
One reason why Tamora is a better parent than Titus Andronicus is the undeniable love and care she displays for her children. Tamora went from being a Roman prisoner to a Roman empress. Some may say this is a demonstration of her ability to manipulate, but correct people say this shows her care for the well-being