My father cheated on my mom and started a common-law relationship in another country and had two other children. After my mom passed away, he brought me and my brother to this country and tried to have us all live as one big happy family, calling this woman 'Mommy'. (I always wondered if my mother knew). 'Mommy' saw us 'new kids' as the step-children and took all of her frustrations at our father out on us, but especially me because I was a girl and, therefore, competition for her daughters. He cheated on her, several times. Both of my brothers followed in his footsteps. Dad and 'Mommy' never married and eventually split up (don't even want to get into the five year legal battle that followed). But I learned from their examples that a relationship started on a faulty foundation will never stand. It also left me with a general distrust of men (If you can't trust your own father, who can you trust?) And 'Mommy' was an example that no self-respecting woman would ever want to follow. It's not worth the mess that it creates for everyone involved, and especially if there are children. Find yourself a man who can be there for you 100%. Your 'boyfriend' will never be completely yours. He will always be tied to his wife.