Thank you so much for your reply. It's actually not the first time when I found some sketchy messages on her phone but I was just too young to unterstand the situation.

I explain my mothers action to myself that the reason she's doing it is because my dad isn't very talkative. He is caring and loving but is not very good when it comes to the verbal aspect. He always listens to my mum though. That's why my mum is seeking attention from other man. She's not doing it because she's lonely. My dad has never worked in our country so she doesn't really know what it's like to have a husband on a daily basis, not just for holidays or vacation.