My understanding is that narcissists do not apologize. They are also not loyal and do not do commitment. So going by that, your partner isn't a narcissist. I personally think that he sounds like a normal, average guy being a jerk. So yes, he is being selfish in those moments before he goes back to being attentive and caring.

It sounds like you are in need of regular support beyond what your husband is able to provide. Having a baby is a hard time for any couple without enough help. I've also come to this forum for giving and receiving support and I understand your need for support. An individual or a couples therapist could also help before this problem gets worse.