How's Your Ex?(2011)

Wakareta Otoko wa Ikaga desu ka?

It took forever for Yoji to get over his ex-boyfriend and former colleague, Tomoe, who suddenly quit the company and dumped him at the same time. But with the merger of their rival companies, Yoji finds himself having to work with Tomoe once again. When Tomoe speaks and touches him as he used to, familiar feelings begin to stir.

(Source: SuBLime)