Am I overreacting?

Here is a little background. My husband and I have been together for 10 years we have two young children together. He works long hours Monday thru Friday. I work 2 days a week, I stay at home with the kids the other 5 days. He is also in a band that practices 2 days a week and plays a show usually once a month. The band just got back from a 2 week tour. I stayed home taking care of the kids, house and his business.

Here are the problems...he is ALWAYS late. He'll tell me he's leaving work in 5 minutes. I've learned 5 minutes to him is anywhere between 10 and 60 minutes. I know he is busy at work so I try not to get mad. All I ask is that he calls to let me know he's going to be later than he thought. For some reason he can not do it! We are constantly fighting about it. It's getting exhausting. Every time he says he's sorry and he'll change.

Another thing he does is that he does stuff without telling/ask me. For example, recently I found out he spent $800 out of our savings to buy a trailer for his band!!! He still can't understand why I'm pissed.

So I just want to make sure I'm not overreacting when I get annoyed and mad with him.