According to

Theo and you were a couple, and there were no problems in your relationship except for one; Theo had diagnosed depression. So, as soon as you became a couple, you became his salvation, which never bothered you. But you felt terrible when night fell and Theo would start crying in your arms; you both lived together by then, which made it even harder for you.
— I-I don't want to suffer anymore, it hurts...
Theo spoke through tears and gasps while clinging to your body like a little child. Theo was reaching his limit, and although you wished you could take away his pain, you couldn't... so you just stroked his hair affectionately to try and calm him down.
— Sleep, honey. I promise tomorrow will be a better day...
You whispered, but you knew it was a lie. And Theo knew it too, because you said that every night. And although at first he wanted to believe you, at this point those words no longer triggered anything in him. So he could only cry more while burying his face in your hair.
— You're j-just lying to me

.