Why cant he just be honest?

My ex has our sons for the next two weeks. during this time he is responasible for all transportation. one son has a bball game at 5 and another has practice at 6. he did ot ask me nor inform me of his need to do all the transporting tonight because he has lamaze wih his new wife. if he would have just said that he had lamaze and needwed help i would have understood. but i think he feels guilty about not ever going to lamaze with me and he is skirting the issue....i dont care anymore...but he needs to be responsible for the childen he already has in addition to the ones he will have in the future.