A lot of us have been there; he smiles at you sweetly, gives you a look that could melt your heart, and you let yourself fall into the kindness.
He tells you, "you're such a good person; you make me want to be better."
Your heart is a flutter, you're drowning in the sickly sweetness of what you take as one of the nicest things someone has ever told you. It's so easy to read it as though it's an admirable thing for anyone to say, but the reality is, no one should be held liable for making you want to be a decent human being except yourself.
It's one thing for people to bring out the best in each other.
When you find your happy place in the company of the people you love most in life, that's one of the greatest things in the world. That example of the "bettering" of one another comes organically. But to only find a desire to be kinder, more selfless, more decent because another person is kind, selfless, and decent is putting way too much liability on the other person, and it means not taking responsibility for yourself.
By telling me that I'm the reason he wants to be a better person, he's putting me on a pedestal that I cannot possibly live up to all the time.
He's holding me liable for his desire to stop his negative behaviors rather than it coming from a true desire to be better. If being with me or around me is the only reason he's decided he needs to get his act together and start being a decent human being, I'm here to tell him that he should really reevaluate.
Because what happens when we break up?
What happens if we have a falling out for some reason or another, and I'm not longer in his life to "inspire" him to be better? His desire to be better disappears alongside me, because his desire never really came from his heart anyway. He go back to the same negative behavior that he had in the first place unless he came come to the realization that being a good person has to come from a real desire within.
I don't have the time to pander to people who can't take responsibility for their actions.
It shouldn't have to be my job to show anyone what being a decent human being looks like. His parents should have instilled that in him when they were raising him, and if not that, he should have been able to recognize elsewhere what kindness and decency looked like in other people so that he could emulate it himself. If he's a grown adult who says he didn't recognize what being good meant until he met you, that says more about him than it does about you.
The point of all of this is simple; it is an extremely important life lesson to learn that you are not responsible for anyone's actions and feelings except for your own.
You are not accountable for the decisions someone else makes, and that's the truth. No one is dating someone with the intent on raising him and teaching him how to behave or exist as a functionally member of society, and no one should have to.
I'm not saying it's a red flag to hear it. Often times it is said with good intentions and sometimes it is meant in the organic sort of way I mentioned before. But my advice if you're ever told this; think about it. Consider it a pink flag, one that makes you do some evaluating before you smile bigly and accept the comment as though it is a badge of honor.
Above all, hold people responsible for their own actions and don't let them make you feel responsible instead.