Parenting is tough

Duh,lol. I had another big ol thing w/ my ex today. I really hate them, I think he likes them, knows I hate them,and that is why we have them,lol.
He called and said, "I want you to bring the kids over this afternoon." I told him I couldn't right now ( dh was working on my car), what was up? He said that he wants Josh and his friend to come stay for a week, and I said let me get my appt. book, and we will try to get something set up. That made him mad from the get go. His brother was in the car, and he was talking to me, but for his brothers benefit. I told him that Josh had an appt Tues. PM and on Fri AM, so we would need to work around that. He was not pleased about that, but we continued the conversation. I said that there were a few things I felt the need to talk to him about, because we had not spoken in awhile. He said ok, then as soon as I asked him about where he stored his guns ( he and I have had previous problems regarding guns, and our boys are teenagers, I want to know how they are being stored) he started saying things like " Stop yelling at me" and "There is no need to get so out of control" Like I said, that was to benefit his brother. I never yelled. He said that he is not 12, he knows what he needs to do, and I have no right to ask him any questions. I feel differently. I feel I have not only the right, but the responsibility. I also wanted to share some things that were discussed during the last session w/ the counselor that Josh and I had, but we never got that far. He made it about him. He said he was hanging up, and that he was going to call Joel's cell phone and tell him about it, so that Joel could hate me as much as Josh and Josh's friend do.
I really think this is mostly about him NOT wanting the kids this week, after he had said to the kids that we should set something up. I think he is starting to have problems again, either emotionally or financially, and wanted his brother to think it is me, not him. I asked him to please not involve the kids in our disagreement, but he called Joel anyway. Joel was great, he said that "Dad people disagree every day, and people get over it too" His dad then said "I don't know how you deal w/ her everyday" That really makes me angry because I do not speak poorly of their dad in front of them, no matter what I think of him. It just stinks for everyone involved.