I look at your dream as if it is a replay, on a different level, of what just happened in your life. However, the dream might give you a different perspective on the situation.
Many people come into our lives during a lifetime. Knowing ourselves and having the skill of observation and intuition about others, we often have a sense as to whether someone will be temporary or permanent. With the temporary ones, sometimes there is the question of who will end it or exit first...sometimes who will be the "bad" guy. Even though it is better for each person for the friendship to run its course, endings are rarely equally unpleasant for both. Each person can be likely to feel they are the more injured party in the friendship and in the ending.
So, the captain might be a part of you that knew what might happen and let it to save your Self. That is what you do to live your own truth and love your Self. However, on a ship the captain is not 100 percent in control despite his 110% effort. The weather, the crew, engine explosions...you never know what could happen on a day to day basis. In the dream, the captain got burned in the friendship...it got to a point where you no longer had any control or choices. Your friend cut you off.
Sometimes men do not know how to relate to strong women and so they try to dominate them, like a boss or captain in the relationship. I do not tolerate that myself and for some men who have cut me off they had to kill the friendship to feel good about them being male. Their disrespect in the ending comes out of their own insecurity. That is just my opinion of course. It is possible he was trying to "captain" you and the relationship.
So, you might possibly feel guilty for not being more upset about the ending or as upset as him. You might feel guilty for not having ended it yourself sooner. You might be angry with him for exercising his control "over you" for ending it.
We cannot control who comes in to our lives. When someone comes to the door, of your Self or your life, even online, you can learn how to ask the right questions to find out who is there and decide whether or not you want to let them in or lock them out.
You are fine and so is he.