Can I get a divorce from my ex without getting a lawyer if we have child support set already.

We have been separated already 5 y @ she has a baby @ lives with someone. I live with someone @ have a baby too. I want a divorce how do I do it fast without her being their. Our child support is set already and we have 4 kids together. @ one is 20, 17,16,12 I have custody of my boys the live with me. She has my 12 y daughter I have medical ins for my kids. Me and her never owned anything together. I'm not behind in child support. What do I do.