What’s a deal breaker

FOR MEN. What’s a deal breaker in a relationship ? THIS IS ONLY FOR MEN!!

& also if you have a baby mom do you find it okay if your girlfriend told you that she wants you to communicate with her as well when you communicate with your baby mom. She doesn’t trip about you talking about the kids but like she’s about to come over and bring something. Is it okay that she wants to know? MEN ONLY PLEASE