People who thought Peeta coerced Katniss into having kids missed important things about Peeta's character. Peeta at no point ever forced or pressured Katniss into returning his affection. Instead he waited and was her friend and whatever else she needed. Peeta was consistently letting Katniss be the leader in what steps they took in their relationship. He was her safe space and when she was finally certain the world was also safe, she was ready for children.