And your if your ex knows that you will be the safety net for these promises, he'll keep making them. The older one already knows.... Keep your promises, follow through with your responsibilities.... this will "make up" for ex's irresponsibility. As sucky as it is when he does follow through and he is the "fun" parent. A child never stops wishing for this or that from a parent... they just learn when not to get thier hopes up.