He's so afraid of losing her so soon after he almost just did. He saw her get taken away and hurt for no reason after almost losing her, can't imagine what that does to someone in such a high position and having no control over the safety of someone you love so much
Yeah, in the end, they're both just afraid of losing each other and are trying to protect one another in their own way.
Maxi can't accept Riftan's decision because she's terrified of putting Riftan and Anatol in danger. And so is Riftan. He's just as afraid of losing his precious wife—to the point that he couldn't care less about anything else, even if it meant going to war against the nobility or even the Crown.
Both Riftan's reaction and Maxi's decision are completely understandable. I can't blame either of them.