That is a double standard.
I believe that when two people have children and they split up and decide to date that they shouldn't move in with anyone new until the child is a little older. You never know who you're letting into your home.
They should be mature enough to be able to meet each other's partners and judge for themselves whether or not they want their child associating with them.

Many a case of child abuse starts out with two parents that have neither maturity or common sense when it comes to dating with a young child in the household.

Yes. Either way the child will be around them at some point.

Well you have the custody but u still have to leave ur kid see his father. And his girlfriend isnt their mom so dnt worrie atleast she being nice to them. Ur his mon not her dnt worrie just calm!!

I agree with villageidiot, & will add that the child should be more important than the parent's sex life. The parent needs to keep the new person away from their child until they are sure the relationship will be permanent, & they should introduce the new person to their child's other parent first. Not to mention checking out the person's background first. If the parent has found a truly great person, that person won't object to being checked out, because he/she will have nothing to hide.

I'd sure want to know what kind of a person was spending time with my child. But suppose the new girlfriend is a really nice person who treats my child well. I can choose to be a jerk and insist she doesn't get to be around my child. Or I could decide than the more caring, loving people that are in my childs life, the better for my child.