Another option could be 'Skip Beat!'. While not strictly mafia-themed, it has elements of power dynamics and romance that might appeal to you looking for something similar. The characters are well-developed and the plot keeps you engaged.
One popular manga with mafia romance is 'Kuroshitsuji' (Black Butler). It has elements of romance within a mafia-like setting.
I'd recommend 'Lookism'. It's not strictly about the mafia, but it has some mafia-related elements and a diverse range of storylines that might interest you.
I think it might be 'The Family Man from the Mafia'. But I'm not 100% sure.
Yaoi manga with possessive mafia usually have intense emotional dynamics and power plays. The mafia element adds a layer of danger and mystery.
One could be 'Kimi ni Todoke,' where the main female character is popular and there's a sweet romance story.
One popular one is 'Vampire Knight'. It has a great mix of vampire elements and romantic storylines.
One popular manga with vampire romance is 'Vampire Knight'. It has an engaging story and well-developed characters.
One could be 'Kiss Him, Not Me.' It has a popular girl as the main character and a sweet romance storyline.
One popular one is 'The Dragon's Bride'. It has a great love story and cool dragon designs.
One popular one is 'Dragon's Love.' It has a captivating story of a human and a dragon finding love against all odds.
Typically, mafia romance manga have elements like power struggles, loyalty tests, and passionate love. The settings are often dark and mysterious, adding to the allure. The couples have to overcome many obstacles to be together.