What would you do if your man is emotionally cheating?

Telling another woman that he is in love with her (his ex who he was deeply in love with), how he misses her sleeping next to him, taking her out, smacking her ass, kissing her,  hugging her, asking her to send him pictures (regular), him sending her a picture, bringing up old memories with her. How would this make you feel?! What would you do about it?