Leaving Neuro ICU - wishing it had gone better

So I've spent my first year of Critical Care nursing in the Neuro ICU and learned a great deal, but also had some really negative experiences. I promised my NM that I'd give them a year, and did - I was really looking forward to some of the promised educational opportunities that were discussed when I hired on - they never materialized - and I was hoping for the chance to expand my clinical knowledge and skills base. Instead it seems like I'm consistently assigned to the heavy lifting patients, the frontal patients who are "difficult", the DT patients - because I'm a male nurse, a big guy, and have prior EMS experience, I suppose. There's a core group of people who make all the assignments, and they and their friends seem to get all the choices and the learning experiences. I understand that things are seniority based, but it becomes a little bit frustrating and more than a little bit discouraging. So I applied to transfer to the Cardiac Surgical unit - and was welcomed with enthusiasm by the NM. This new assignment will give me opportunities to advance my career and give me the foundation I need to apply (eventually) to my Masters' program as a Critical Care NP or a CRNA, whichever path I choose.

Unfortunately, my conversation with my current NM did not go so well - while I wanted to be the one to tell him about the transfer, apparently someone else beat me to it, and he was unhappy to say the least. I wanted to leave on better terms. Turnover in the unit is rather high, and he's running pretty short going into the holidays - which doesn't make me feel any better about my decision, either. On the other hand - I had to take the opportunity when it was offered, right? The whole thing has just turned into such a mess.