Low morale

Is been coming to three months since I have give birth. I gained 30kg. Lost 10 and starting to get back into my workout rhythm. My husband is not really a hands-on father. Instead of learning how to feed our son or even carry him... I caught him looking/checking out half naked models on Instagram.. I’m so disappointed. I ruined my body to give him a son but he looks at other woman. Am I the only one going through this?