I have a Multiple-entry Type D visa for a country in the Schengen area. I am aware that I have 90 days within an 180-day period to travel around the Schengen area. I plan to visit Italy during this time, but decided to join a spring break trip to Romania and Bulgaria that has me return to Italy for a week before returning to the country associated with my visa. This trip takes place one week before Romania and Bulgaria join the Air Schengen program.
Is it okay to re-enter the Schengen Area in a different country than the one that issued my visa and then stay in that other country a week before returning to my visa country? Or does the multiple-entry type D visa always require you re-enter the Schengen Area in the country that issued it?