Aw, man, that's a hard decision. It's good of you to do that, though.
Stick around, everyone here will share what they've learned over the years...and maybe you can get a different leo when you won't have that in-over-your-head feeling, since you'll be more prepared, then.
He won't be Cerberus, no. But I think you'll be doing right by him.
I'm sorry this decision came to you, it must hurt.
I recently had to put down my first failure to thrive gecko. I bawled like a sissy.
But I was acting out of love, I didn't want him to hurt anymore. It's not easy, but it's the right choice.