I feel like some of the "I would never do that" posts are coming from people who haven't yet been a situation where it was the best option.
Last year, my kids and I lived apart from my DH for 2 months during a move. He HAD to move for work, and we really felt it was best for the kids to wait until the end of the school year. One of our kids has special needs and transitioning her with 5 weeks left of school, or moving the day after school let out would have gone badly. So we let her finish the school year, have a mellow couple of weeks to unwind, and then moved more towards the middle of the school break.
It was hardest on my sweet husband, who missed me and our kids very much. We saw him once during that time -- the kids and I flew down so we could visit him and see the new school. My DH and I had to decide if him seeing us several times was more important than the kids getting to visit the new city just once because we couldn't do both. We decided that it was more important that the kids see the new city, new school, etc. One of our DDs had a birthday while we were living separately.
Sometimes what is best isn't what is easiest.