Jay hated how close you and Voight were because it felt like he couldn't do something without Voight getting pissy at him. He was convinced that's why Voight just didn't like him general.

Jay couldn't control the factor in which you were his partner and he was yours. You had never done him wrong - mutual feelings but Voight was just ALWAYS there.

Jay sighed, seeing the tension between Voight, Dawson, and you against this case where a gang member was involved - it seemed personal, to Voight anyway. But it wasn't his place to ask.

You were stuck late at work one night and he noticed, "Hey, are you okay?" He asked, walking over to your desk and taking the file out of your hand to look at.