It sounds like the truth spell you did worked a treat! 
Astral travel usually happens, like you said, when we are awake. In other words, entering a trance and leaving your physical body, traveling the world through an energy body.
To me it seems like you had a really vivid dream! These sometimes are caused by your subconscious processing recent events. If you cast a truth spell before going to bed, it can trigger these really vivid dreams, not to be confused with lucid dreams.
I know you said you had a separation but I’d be curious to see if he had a similar dream recently…!
On the other hand,
To dream of saying goodbye seems like a sign that you are letting go. It may also symbolize big changes ahead! 