@ L: How nice for you! Let me try to explain: On a birthday-party for a child over here in Germany, this child is honoured by a song with the wording:

Wie schön, daß du geboren bist,
wir hätten dich sonst sehr vermißt;
wie schön, daß wir beisammen sind,
wir gratulieren dir, Geburtstagskind!

I think that "Schön, daß es Dich gibt" stems from the idea in this song . . .

Also, "I'm so glad you are around" seems to be quite a good fit.

Also the closest I can think of. It's not that serious; you can even say it teasingly to people in your own family.

If you want to be more serious, Wilma's suggestion is okay, or something like 'I really appreciate you' might work. Even 'I'm really glad that you exist' would probably be okay, though it's not a very common thing to say.

Poor attempts at romanticising this wonderful German guy's style - does he give lessons?

The world is a richer place for your presence in it;
That you are in the world is a wonderful thing;
Your absence from the world - darkness; your presence in it - glorious light.