R&B: "That's. How. I. Know. I. Love. You."

It's R&B/Soul (I think?). US, 2000s-2010s. The beat sounds similar to "Pop, Lock & Drop It".

It's a man who sounds similar to Robin Thicke or Maxwell (high-pitched voice).

What I believe to be the chorus is sung with emphasis on each individual syllable which I will try to illustrate. The words are not exact, but a very close approximation:

"Ba-by-that's-why I love you... (?)
Cause-(da-da-da)-you love me still (?)

That's-the-rea-son I love you... (?)
Da-da-da, you love me too (?)"

His voice sounds like Robin Thicke (Lost Without You) or Maxwell (A Woman's Worth).

Thanks so much.

I still can't find this song but I can't stop looking for it! 🫨🤳