Most people who dream of extra-partner relationships worry in relative silence and anonymity about their promiscuous minds during dreams. But here you are, betrayed by an unusually active body during sleep! Can there be no privacy?!
Sleep-talking is considered a fairly benign, though still uncommon, accompaniment to dreams. Usually our muscles are inhibited from moving during dreams through a process called muscular atonia. (Translation: muscles without tone.) If the inhibition is incomplete, though, a category of bizarre behaviors can result. People can jump out of bed to fight off dreamed intruders and attackers. They can sit up and suddenly begin slapping the covers (and their bed-partners), believing they are putting out imaginary campfires. And, as you know, they also can talk in their sleep - often saying things they later wish they hadn’t!
Sexual attraction to an ex is nothing new. In fact, it’s one of the main reasons many of us often “hang on” to relationships that we know, otherwise, are unfulfilling. What is intriguing about attractions to ex’s, however, is that our ex’s usually are more attractive when we are experiencing difficulty in our lives and current relationships than when we are not. What’s the logic? We don’t like the looks of the future - so we find a retreat to the past comforting.
Judging from your dream report, it appears that you really don’t want to go back to being involved with your ex. In this light, I agree with you, that your dreams are symptomatic of stress in your current relationship, rather than reflecting a genuine desire to rekindle old fires.
Anyone who has been involved in a romantic relationship and had to “move on” will understand the occasional tug of a past lover. Reassure your partner that your life is about moving forward - not backward. Tell him also though, that if he wants to join you on the journey, he needs to begin sharing the responsibilities of your relationship.