The tendency to return feelings and attitudes that are expressed about us, or to seek what we perceive as a "balance" in a relationship between others' feelings towards us and our feelings towards them is called:

Reciprocity

Explanation: Reciprocity can be simply refered to as the reward for a just or noble action i.e a good gesture in return towards a good action.

For example, when a person does something good to you (good action) you tend to want to repay that good action with kind gestures or actions as well.

Trying to balance the feelings directed towards you and your feelings directed towards them, This is called reciprocity