Need some advice....

Me and my so are both 21/22. We’ve been together for almost 3 years now. We have 2 babies together that were born back to back. We’ve always been a loving happy couple. We got an apartment together in the beginning of this year, things were going good for us. Recently we can’t stop fighting. It’s something everyday. I’m very moody towards him and he’s very moody towards me. We never ever get time for ourself anymore which is what we expected. But i just feel like we’re loosing that spark that was once there.... I love this boy with all my heart. All we ever wanted since we got together were children. Now that we have that, it’s like our relationship is falling apart. I couldn’t see this man with someone else, I couldn’t imagine living everyday life wihout him. But idk why I feel so unhappy. I don’t like the way he talks to me most of the time. I’m always bitching at him. Idk what to do anymore.... he’s also the type if I try to talk to him about my feelings he doesn’t give a shit about how I feel like he used to now he’s just like “well you do this...” or “you do that” he always turns the blame on me like I’m the only shitty person here. He’s hard to talk to, or maybe I am? Idk anymore.