These emotional connections often arise at work or in a social context in which working intensively toward a common goal consume energy.
Here are a few observations of the "just friends" emotional affair:
This person often struggles knowing where to draw the line. S/he often throws him/herself into something 100%. Other aspects of his/her life may suffer or be ignored. There often is a lack of personal balance between family, work, self care.
Of course the "just friends" comment means either "stay away" or I'm, underneath all this, really confused about where I fit in relationships, what I want from them, or what they mean to me. There is an "emotional connection" to the OP that defies description. A sad kind of "stuckness or lostness."
The common complaint to the partner is: "I feel badly about this, and I don't want to hurt you, but, I'm not "in love" with you anymore. "I love you but I'm not in love." This often indicates:
This person usually has a need for drama and excitement. Life easily becomes a soap opera. Emotional juice from the fall-out of emotionally intense relationships reigns rather than living life from the core of who one is.
This person needs to be adored, or think another adores him/her, because there is a lack of inner strength and solid identity. The other becomes my world, because I lack a world. Being 'in love' is the panacea for my emptiness.
There are many subtle differences in affairs. Emotional affairs are only one kind. Once you begin to see and understand the differences, a new sense of empowerment overtakes you embark on a more confident path of resolution.