When Sbarge talks about "rip your heart out", I mean, the most logical example is the cheating fallout.
Imagine, for a moment, that you're Kaidan. You watched the beautiful, tough as nails commander from afar, and were drawn to her. Then you fell in love with her, and she with you! Together, you stopped Saren and Sovereign. You don't tell Shep, but you daydream a little about the future, and then Shepard *dies*. Your beautiful, one of a kind woman, *dies*.
Two years later, she's alive, but she's working for terrorists. You're sick to your stomach, and your lungs feel incapable of taking in air. But yet, she's alive, and your heart aches just a little, from the possibility of happiness. You see Shepard again, and two years of mixed, messed up feelings come bubbling up to the surface. You don't handle it your best, but neither does she. But perhaps, just maybe you can reconcile after this mission she's on. Because she's Shepard, and she's beautifully complicated.
When she, miraculously, survives the suicide mission, by this time, you've had time to open your heart again to hope. Then, you find out that she cheated on you. Your two years and several months of agony, and she's with someone else. You realize that perhaps, you never meant to her what she meant to you. You feel sick all over again, and find yourself wishing that she hadn't come back from the dead after all...
Or there's other explanations, in which Kaidan can get killed off. But, I don't know, I just don't feel like we're going to get funneled down that path.