ex to be is always out of the country and seems to think it is acceptable to see the children aged 5 and 7 for just a couple of hours whenever it is ok for him, he wants to see them tomorrow before he goes off for 3 weeks and i rally feel like saying NO i cant talk to him, he is a bully either by text or will just be horrible to me when he sees me what do i do
It isn't acceptable but I think you should still say yes. A couple of hours when he deigns to see them is still better than nothing and if he is off for three weeks the children should get to see their father.
Grit your teeth and don't let it get to you. Think of it as you doing something that is good for the children. If he carries on like this they will see him for what he is when they grow up.