Get an attorney. This can't be easily answered in this forum. There is too much additional information needed, plus lots of extra dialog. Start by keeping DETAILED records of EVERYTHING going on, names, dates, times, letters, emails, etc. DON'T do stupid stuff. This includes, but is not limited to: loosing your temper, making threats, sending letters or email that can be used against you later, personal activities which call your abilities as a parent into question like clubbing, drinking, pornography (internet pornography as well), dating someone else, being seen with another woman in any way which could be considered compromising (including lunch, dinner, movies, her house), don't get another woman pregnant, being seen with another man in a comprimising situation (hey, I gotta mention it in today's day and age). DO YOU GET THE PICTURE WITH THIS? You are a man. Act like one. Take responsibility and stick to it NO MATTER WHAT SHE DOES. If nothing else, when your kids are grown they should be able to look back on these upcoming years and be able to think: Dad never missed a child support payment and never missed my birthdays, Christmas, Graduation, etc. Not knowing your situation, all I can say is that if the worst comes into play and you don't ever get to see your kids, or rarely do, then all you are left with is your honor. DON'T COMPROMISE YOUR HONOR. Actions speak louder than words, though they will not guarantee a happy ending. If it's coming down to a divorce, ideally the two of you should work something out together and MAKE IT LEGAL with attorneys, preferably prior to divorce court. If it's to be an evil, knock down, drag out divorce, keep your head, follow the guidlines above, play by the LEGAL rules as opposed to your heart, find a good attorney who will take the time to understand your desires and fight for them and then FOLLOW HIS ADVICE. Other than that, try to keep the lines of communication open and good luck.

She can not legally not let you see your kids unless they is some type of order against you, You need to keep records of the situations where you try to go see them and she wont let you, take them to your lawyer, and or the police. What she is doing is border line criminal, unless she has something against you that deems you an unfit parent. And You might want to take this to court, and explain the situation telling the judge she refuses to let me see my children and im helping them by paying child support, because its not moral for a man to pay child support for there kids and not be able to see them. Good luck to you.