if this is what it looks like 'finally starting to get better' it must have been drama central at the beginning!
i'm sure there's a ton of stuff unexpressed here, but just going on the bare bones of the post, you are quite right. i can't imagine my husband making plans to fly somewhere and not discussing them with me first. we never had the blended family issue to complicate matters, but common courtesy and more, common sense dictate that partners communicate the details of their schedules to each other. hell, even roommates generally do that much.
is it possible you've thrown a fit when he's made these plans before and that's why he's sliding around the blow-up now? if so, face THAT head on before assigning blame. of course, he's still not right in trying to simply not discuss a potential problem, but make sure you're not the cause of the drama.
if y'all have been together for two years, and this is what it looks like as things improve, it honestly sounds as if you didn't go into it thoughtfully and with preparation, both as a couple and as co-parents. the upheaval is not good for the kids and deadly to your marriage. i suggest you work on developing much better communication tools. you need a strong family and parenting philosophy, and to create a paradigm for making sure you're being clear and respectful with each other, modeling it for the kids. an example would be to plan to discuss the upcoming week's schedule with each other over the weekend, making sure that chores and extracurriculars are made clear to everyone, and that you use good communication hygiene such as using 'I' statements and mirroring.
there's no shame in getting a counselor to give you a hand in setting this up.
khairete
S.