Tengen knew the risks that came with being a hashira, or even a demon slayer in general but all he knew was his prior life as a shinobi so this was the closet thing to that he could get. Well, the closet who could get to that without hurting innocent people. Instead he wanted to save those people in the flashiest way possible.

After becoming a demon slayer then a hashira, he reclaimed his identity as he fought and risked his lives to save people he wanted to, refusing to live by the rules of others. But of course, after his first marriage with you he could no longer throw his life away without the thought of someone else coming to mind. With you in his life now he no longer lived for himself. He lived for you.

And he thought you worried far too much.