Science has yet to figure out why we dream. Any answers about dreaming and it's meanings are mostly just ideas and guesses to be honest. I won't go into all the guesses as to why we dream, it's possible importance to our general health nor the mechanics of the brain.
When we are awake our brain filters the information it receives in a number of ways ... and every brain is different. For example when awake we may not see the deceit of a friend or family or stranger, but when we sleep, the filters (it is believed) are mostly turned off and we can see without the emotion, judgements and so on. The brain picks up information we are not even consciously aware of and so it is not to insane to suspect that when you dream of something personal it is your brain showing you (purposely or not) information you may have missed or showing you a different angle you refused (via filters) to see when awake.
So yes to question one .... the problem though is interpreting the dream accurately when awake and the filters are back on.
In regards to the question about the man you dream about ... I can only really think of one thing and that is fantasy is always better than reality because in reality you control only one person, yourself. In dreams you control the man as well and could theoretically change small pieces to make him more to your liking. You know? Like change that tone he uses when he is tired of your talking, or the way he smells sometimes, or that annoying teeth clicking or whatever... your fantasy man is your creation, your reality man is ... well his own man.