Kristin Cavallari isn't happy with Jana Kramer going on a date with her ex-husband, Jay Cutler.Cutler and Cavallari announced their decision to split after 10 years together in a joint statement last April. Cavallari has since moved on with country singer Chase Rice, but a source tells ET that she's blocked Kramer on Instagram after she went on a date with Cutler because she had previously thought of Kramer as a friend.«Jana and Jay did go out on a date in Nashville,» the source says.