I am doing ok with NC (hard but coping!) . Yet, I am mindful that I may be now trying to play my usual hot and cold strategy with my tango partner. For my progress in tango, I need a partner. And when I met a guy who I find very comfortable to dance with (whihc does not happen often) so I was happy that I coyuld practice more often and improve my dancing. But soon I felt that he was seeking intimate relationship with me. I spoke with him straight away that I only wanted dancing and nothing more. He agreed to my terms but I feel that even dancing with him creates havoc within me as I suspect he might be secretly hoping to "tame" me and through extablishing friendship to move further on. As I know too well that mechanism I am very sensitive to other people's subtle manipulations. I cannot blame him for breaking my boundaries but I find myself "on guard" with him every time he is sharing his personal details with me or is too eager to offer help. I sense there the need of a hungry person who lacks intimacy and might be love addict himself.
My narcissist part might be using him to fulfil the need of admiration...
Since, from my perspective, tango dancing is a physical one-on-one activity, this is a tough one.
When he begins to share personal details, attempt to shut it down. Do not acknowledge his personal details. A simple, "Oh, yeah - well, what about this step we have to do next?" (or whatever terminology you use) may be useful to redirect the conversation.
Of course, if you sense he is too eager, he may be too eager. Either way, you are in control of what you do. He is not.