Armin should be with Annie, considering that all this time he really liked the girl, but recently their relationship has plummeted and become destroyed, the relationship is unhealthy and toxic.

Because of that, Armin chose to break up with Annie, after all, he only liked her and didn't love her. A few months later Armin found his love again,...she was kind and innocent...

This is what is called true love... even though the downside is that the girl is pregnant with someone else's child.