Any loving parent hurts in an agonizing way when they have to be separated from their children. My daughters are 11 and 7 and I see them on weekends and for longer stretches on school breaks. I know what you're going through. It sucks.
If it helps, other things suck that we can't control, like death and cancer and pandemics and hurricanes and wars. You just have to maximize the time you have with your kids and try to give them an opportunity to be happy.
Usually, people calm down after a while and you can have civil discussions with the other parent at some point in time. Until then, stand firm, don't cave on things that are important, but don't descend into petty reprisals. Follow through with any agreements, and don't threaten something you won't do if she ignores the threat. At that point the ex will respect you - and you really shouldn't give a shit about anything beyond that.
ἡ δὲ κἀκ τριῶν τρυπημάτων ἐργαζομένη ἐνεκάλει τῇ φύσει, δυσφορουμένη, ὅτι δὴ μὴ καὶ τοὺς τιτθοὺς αὐτῇ εὐρύτερον ἢ νῦν εἰσι τρυπώη, ὅπως καὶ ἄλλην ἐνταῦθα μίξιν ἐπιτεχνᾶσθαι δυνατὴ εἴη. – Procopius
Ummaka qinnassa nīk!
*MySmiley*
