Can my babies's mother take the kids from me when I have been the stay at home parent for most of their life just so she can get child support from

I'm a father of a 3 year old and a 5 year old. I quit my job so I can stay home and tend to them. A year after my oldest was born and have so ever since. I cook for them I clean up after them and changed their diapers when needed. Their mother went to work because she wanted to be the one who did and she never wanted to stay home with them. Now she has gone back to school full time and she is planning to leave me and take the kids from me and hit me up with child support. We are not married. She wants to be a single parent to get more government assistance. What should I do? . She even goes out and party at bars friends or where ever else. I haven been to a bar since before my youngest child was born.