Help!!

Hey guys, I’ve asked this before but I got no answers.

Does anyone know about this manga?
Both main characters meet and fall in love when they working together in the coffee shop. Then the ex girlfriend of the male character appears and works at the same shop too. One day, the shop was on fire, the male lead did not save his girlfriend, but the ex-gf (because he did not know that she was inside too). When he realizes and tries to save her, it was late. The ceiling was falling, and his ex-gf hold him back. The female character was rescued by someone else. The moment she saw her boyfriend and the ex together, she feels she lost everything.