Termination of Support: Tricky Situation

I have a unique situation. My ex-wife and I have been divorced since 2001. We have 2 children together. 1 child is 21 and the other just turned 18 and is in their senior year in high school. Our court order was from Delaware. I have been paying support from the time of the order and have no arrears. Our oldest child turned 18 3 years ago. We received a letter from the state saying the obligation will stop unless certain items were met. The child joined the military at 18, but the support has continued to this day. Our other child just turned 18 this year and will be out of high school in June. I received the same letter for her. I have also been informed that she is over 5 months pregnant and due in July. Now both of us have moved out of the state where the support order originated. She moved to Colorado and I moved to Virginia. My ex has contacted me asking me to continue with the support for what I am paying now. She has threatened me by taking me to court in Colorado as their laws state the support ends at 19 regardless if they are still in High School or not. I do not mind continue helping our child, but do not agree with the ultimatums that are lashed out. I also have been giving her an additional $50 /week for the last 3 years to help with medical/ school fees. This has been automatically coming out of my bank since then. Can someone help direct or guide me in the right direction? Not sure what my options are at this point and need some help deciding. Thanks in advance

Termination of Support: Tricky Situation