Terry Milkovich has always been against Mickey embracing who he truly is. In Season 3, Terry forced Mickey to have sex with Svetlana while Ian watched at gunpoint, in an attempt to force him to want to be with women instead of men. Terry has never been shy about his feelings regarding homosexuality and he had a similarly revolting response when Mickey formally came out in Season 4.

Things came to a head in the Jan. 19 episode of Shameless, when Terry and Mickey pulled guns on each other and Terry threatened to kill him if he marries Ian. It’s unlikely that the threat will make Mickey call off the wedding, but Terry is so violent and unpredictable that he could physically stop the wedding when the time comes.