Collars tell no lies.
I like the way you involve the senses in this, Bri - the senses of smell and sight. The lady can smell the perfume and see the lipstick imprint, and it's all too easy to figure out what's been going on. As usual, your imagery shines; "crimson flicker of infidelity;" "his gaze wept the truth." Then the corker, for me, is the seeming contradiction: "Breathing in the sweet smell of goodbye." It doesn't seem that goodbye would be a sweet smell. And yet it makes sense - if he's cheating on her, she would likely want to be rid of him, and that would be, if not sweet, at least bittersweet.
Nice. A very well-crafted poem, especially given the constraints of the "55." Great job.