I think it sounds normal. My husband will ask me a couple days in advance when he's planning on seeing his girlfriend. It avoids scheduling conflicts, and keeps us from intruding on each other's private time. We just see it as a way of being polite to everyone involved.
Althought I do have to admit that Husband did schedule a date for with his girlfriend for my birthday - when I mentioned that, he called her right away and changed it to the next day. When he told her why he was changing, she told him he was a dumbass for forgetting my birthday.
It works well for us. If you're feeling left out, or like you're not getting what you need, let him know. I'm finding more and more that assumptions about what each person expects will get you in trouble every time - it's best to speak up.