This paper proposes an exposition of the phenomenological foundations that allow a reflection on the intersubjective horizon in L'Etre et le Neant. In this context, the detailed exposition of the central argument that in the 1943 work is presented as a conflict between being-for-itself and being-for-other is not an objective. Rather, the aim is to delineate the arguments that lead Sartre to propose an original affectivity (pre-reflexive) in this work, from previous works on emotion and the experience of the face of the other. With this, we propose a reading of intersubjectivity based on desire as a fundamental transcendence.