Not that I could give you advice on what to do, but maybe I can help you think about some things.

I'm the same age as you, but I'm a guy, and I don't have kids and never been married. But I can tell you, that my parents divorced when I was four and my sister was eight. Different reasons, my dad came out of the closet, so, obviously my mom couldn't stay with him. But eventually, like two years later, my step-dad now came into the picture. Honestly, he started to become the father figure to me, and a respectful loving husband to my mother. My dad was a weekend dad, and yes, I had my issues, but he ended up living in a different state anyway.

What I'm getting at is that I feel it is important for kids to be around a somewhat functional loving environment. Afterall, how will your kids be with others when they start dating? You are their role-model in many ways, and to see you happy and in a loving relationship is a good thing because they will seek out that as well when they are older. Does that kind of make sense? Honestly, nothing is ever easy, and my parents divorce was alot harder on my sister than it was to me because she was older... but if your boyfriend loves your kids, thats great for both you and them.

Good luck, I hope this helps somewhat!