Me and my ex both have parental responsibility for our two children. I however look after them both full time and he see's them one day at weekend and one weekday evening. He will be paying for them both soon, so that isn't an issue. I just don't want him to be able to take the kids away or abroad with out my say so. He is very temperamental like that

Unless he has block time with the children like in the summer or something then he can't remove them from the country. It takes a permission anyway. As far as where he goes during his time with the child then its really his business unless it is written otherwise in the court orders. Like being notified if leaving the state etc.

If he tries to keep them beyond his time and without reason and proof then that would be parental kidnapping. You would have the full force of law on your side.

What you don't say is whether this time division is by court order or not.

But he can't take the kids out of the country without both parents permission.

Also, if the court has ordered you primary physical custody then he can't take them without violating the court order.

Me and my ex both have parental responsibility for our two children. I however look after them both full time and he see's them one day at weekend and one weekday evening. He will be paying for them both soon, so that isn't an issue. I just don't want him to be able to take the kids away or abroad with out my say so. He is very temperamental like that

In order for a minor child to obtain a passport, both parents need to be present and sign a form giving their consent. There are varying circumstances if one parent is unable to appear, but the bottomline is that you need to consent - he can't get them passports without you saying it's okay.

As califdad already noted, if he tries keeping the children then he's going to be guilty of kidnapping - and the judge won't look kindly on that.

Be advised, him keeping them a few extra hours won't automatically get you custody. It's a pain for you but it's not grounds for termination of parental rights on his part. I'm just playing the devil's advocate for your sake- I've seen people try to get sole custody because their children were playing "Mature" rated games at the other parents' home and obviously, the court wouldn't hear it.