What are the odds that a judge will grant visitation to him?

My husband and I are in the process of separating due to his infidelity. Our children are one and two years old. He is saying that he wants to have our children the same visitation as his 13 years old (from a previous relationship). This would be basically all major holidays and every school break plus the first, third and fifth weekends of the month. I am currently a stay at home mom and I care for our children in every way. He goes to work before they are awake and come home after they are asleep. I am planning on going back to work once school is back in session since I work for a school. I’ll be working four hours a day and take them in day care while I work. My babies are so little and they are used to me being there, not to mention when his 13 year old is here, I’m the one who takes care of her when he works.