As far as your 18 -year old daughter is concerned, it is my understanding that your wife cannot legally prevent you from seeing her because your daughter is an adult. It is her choice whether or not she sees you, not your wife’s. When it comes to your son, that’s a different matter because he is still a child.
Here’s what I recommend that you do. First, get legal counsel. If you can find a lawyer to represent you, great, but if you can’t, go to Friend of the Court and hash this out. There are strict legal guidelines that you and your wife must adhere to and these vary from state to state. Legally, if your wife can’t prove abuse or neglect, then you have the right to see your children. Your responsibility, however, is to financially support your children. I know that you are strapped for money, but that’s the law.
Aside from legal intervention, there are things that you can do to improve your relationship with your kids. Make sure that you continually reach out to them via phone or email. Your daughter can see you anytime she wants, so work hard to be kind, never criticize her mother in front of her and let her know that both you and her mother have made mistakes. Let her know that you want to work hard to make things right. Ask her what you can do to improve your relationship with her and then listen to what she says and take it to heart.
As far as your son goes, if he sees that you aren’t willing to financially support him (handing him money periodically doesn’t count) he will feel neglected. I know that you hate handing money over to his mother but that’s part of the deal with divorce, if she gets custody. If you don’t do this, your son will feel that you don’t care about him. So, again, you need to let him know that you will do whatever it takes to stay connected to him.
Divorce turns everyone upside down. As hard as this is for you, it’s twice as hard for your children. They don’t know what they think, feel or want. They feel that you and their mother have let them down terribly and they will be very angry for a while. You must be strong enough to handle their anger and ride with it. Give them time and never stop reaching out to them. Many fathers become so discouraged by their ex-wife’s anger and their children’s confusion that they give up and become estranged from them. Don’t let this happen.
Whatever you need to do to stay in your children’s lives, do this and fight hard. Get a second job to make more money. Move closer to them. Get a lawyer or go to Friend of the Court so you have someone to help enforce your legal rights. Most importantly, show up in your kids’ lives wherever you can, like concerts, sports events, and birthdays, etc.
I’ve seen many fathers in your situation and I can tell you, that you absolutely can keep a relationship with your children if you put your own feelings aside and focus on what they need.