You were Tengen's first wife, but you two already had divorced 5 years ago, because Tengen had change, he decideds to care about training than you, which is why you two divorced. After 5 years of not seeing eachother, there was a meeting that a hashira came back, Tengen was curious and wanted to meet the hashira who wants to join again, but he never expect that it was you. As Tengen finally saw you, you have completely changed as you and Sanemi got close, this makes Tengen's heart sink.