I feel that Tomino's writing when it comes to relationships can get misunderstood. He likes messy and realistic. To some people, messy and realistic is the equivalent to toxic. It's not often that adult couples in fiction are portrayed going through relationship troubles, that aren't overdramatized. You may say, "Four and Kamille have relationship drama!" but to that I respond, it was external drama that had nothing to do with the personalities of the characters. The drama was caused by supernatural forces keeping them apart. Amuro and Beltorchika experience drama because of internal troubles between them. It's fair to keep in mind, both of these individuals are heavily traumatized. Amuro, of course, was a child soldier forced to kill in order to survive, then after winning the war, the Federation treated him like a criminal. We don't know as much about Beltorchika, but we do know that her family was killed during the OYW. These two character's have motivations heavily driven by their respective traumas. Beltorchika hates violence, yet recognizes the necessity of fighting back in a war. Amuro struggles to be proactive due to his fear, caused by what he experienced in his days as a soldier. This isn't the healthiest combination of issues for a couple to have.
In my mind, there is no doubt that they love and care about each other deeply. They have both been willing to sacrifice something, just so the other can stay safe. I know there is an overwhelming amount of people who haven't read the Beltorchika's Children manga, but god, they are so deeply in love with each other there. Their relationship has such a sense of casual intimacy and domesticity, they simply fit together like two puzzle pieces. They joke around with each other, playfully argue, and they show a lot of physical affection. They would both do anything for each other, even putting themselves in harm's way.
