So: Being is always being-in-contact. Contact presupposes a prior separation, and neither precedes nor overcomes it. Contact is never established or given as presence, it is (only) the rhythm or vibration of its own touching and separating, its own touching (even poignant) separation.
Separation has a certain priority in this story. Not: Being first, then relation. Nor: Subject first, then contact. The subject is “subject to the outside,” as you say, always already. Which means that the touch (without which the alterity of the other would not impinge at all) is already withdrawing in its very touch, vibrating away again and becoming, intrinsically, a trace of itself, a trace of touch.