Yes. The teenagers, an old guy saying this too much often would be unbelievable. That's bad grammar because usually you don't give "ing" to a stative verb, I mean mostly. In this case the speaker is trying to use a slang tone of voice to express his strong affection at the moment being, stronger than ever. If your hound just won the prize in a race, you went up, hugged her, you'd say, man, I'm lovin' you!