Adult advice appreciated - Are a boyfriends misbehaved kids a dealbreaker?

Myself, the mother of a 13 year old boy and an 11 year old girl, also with a man that is not their biological father, but loves them nonetheless. Anyway it is my experience and belief that if the two of you do not have similar parenting styles it will ultimately create tension in your relationship. My husband and I parent with our love and discipline in very much the same way, so there is harmony in our household. Also the older the children get, they will begin to see that the two of you don't agree on parenting methods, and as much as I hate to say it, they will use the two of you against each other. Keep in mind also that if the two of you are together when you go into labor and have this little girl, he will most likely think that he has some sort of parenting rights and decisions when it comes to her. I say jump ship if you can not convince him to change some things, and no your not a bad person because your putting your daughters up bringing in front of your own happiness, and other relationships; this my dear is what good mothers will do. Good Luck