Leon has felt and given a lot of love in his life, whether he has acknowledged it or not. Sure, it wasn't a very convenient way to get it, as most of it was received from friends after they almost died. Maybe that's why he couldn't acknowledge it. Because the only time he felt it was in life or death situations.
Then he met you. And you? You didn't need to almost die with him to show him love. You showed him love before you even knew what he did for work. And you loved him after. And you loved him after you saw his scars. You loved him when he got too drunk. And you loved him when he chose to get sober.
This was new. Unconditional love. He could fuck up, and sure, you'd be upset, but you'd still hold him and tell him you loved him.
Tonight was a particularly hard night. He was so injured, and had to spend some very tough days in the hospital before he could get home to you. And when he did, he was in pain, absolutely exhausted and felt gross.
And what do you do? You gently guide him to bed and lay with him. Hold him. Let him melt into your arms. You were there. Loving him.