Am i a bad person?

Ruthie
Okay so my boyfriend and I mostly grew up together. We are from the same town and had the Same friends and even went to the same school. Stuff went down with his family that he had to move 3 hours away. When he came back he brought back a girl that he had gotten pregnant. She made him move back to her home town away from his family and friends where they got married and had 3 kids together. She ended up cheating on him so he left and came back home. My problem is that we had started dating again since we didn't get the chance the first time and now we live together and we have his three kids and mine too. He's still legally married and every time they fight about something she always brings up the fact that they are still married and he has a girlfriend. We are ttcing and wanna get married our self but she won't sign the papers. Am I a bad person to get with a married man and ttcing and take care of her business?