You messed up when you offered the money before you were sure you wanted to. A person’s child is usually the most important thing to them, and a custody battle can be physically, emotionally and financially draining. When you decided not to help him, it was as if you turned your back on him and his children. On the other hand, he shouldn’t have asked you for the money in the first place.
A man’s primary purpose is to provide, so before he tries to build a relationship with you, he should concentrate on stacking his money and rolling solo until he’s on his feet. If he’s asking for money, but he’s in a position to pay you back, and you really care for him, then help him, but make it a loan and get it in writing.