Do not use the kids against him.

Your children did not ask to be here, nor do they need to be involved in the details of your relationship. You do not have to talk down about him, put him down or tear him down in the eyes of your children. Kids are smart, and will figure things out for themselves pretty quickly. When you use your children as pawns in your relationship, it can affect their self-esteem. It can make them feel a lack of security, and cause them to worry. It can also affect their future relationships with men and women, causing them to be resentful, spiteful, and distrusting.

Using your children as pawns also teaches them that it is acceptable to use and/or manipulate others. They learn to become calculating and undermining, they lose their character, and they lack the integrity they should have – they use whatever it takes to get ahead. They become that person that you cannot trust, that person whom you always wonder about their true motives, because you taught them that it is alright to use people for their own self interest and personal gain. You have taught them that it is alright to walk on people and treat them like dirt. Remember, children learn from observation, association, and their environment; they learn from cause and effect. In other words, the apple will not fall far from the tree.

Do not be Young and Dumb or Old and Stupid.

Ahhh, youth. Sometimes when we are young, we do the dumbest things. This is usually due to ignorance, a lack of knowledge, or a lack of experience. Hopefully, we learn from those experiences, and make better decisions.
However, there are some who still make stupid choices as they age. You many times attribute these choices to stubbornness, being set in your ways, unwillingness to change, or refusing to listen. Remember, whatever decisions you make, whatever choices you elect, YOU WILL HAVE TO LIVE WITH THEM! So learn from those experiences, and make better choices.