If you're looking for manga similar to Happy Marriage?!, you might like these titles. All recommendations are made by Anime-Planet users like you!
Plain Kaya Satozuki has just accepted a position as a secretary for Kyouhei Touma, a young company director whose lecherous ways are renowned. While she initially believes Kyouhei is just a typical, lustful man, Kaya soon discovers there's far more to Kyouhei than meets the eye: he's a vampire, and he requires the blood of women to survive! However, he doesn't kill them - he seduces them and bites them gently in the climax of pleasure without leaving any marks behind. Now that she knows his secret Kyouhei insists she stay on board, scheduling his ‘meals' in tandem with her secretarial work. But soon, Kaya finds herself falling for Kyouhei and helping to feed him when needed. Thus begins Kaya and Kyouhei's troubled yet thrilling relationship that is filled with trials and tribulations aplenty.
Smut. Smut. Smut.
Both have female leads to enter in a romance with the president/director of the company, have secrets they have to manage, and loads of drama (and insecurity) along the way. If you liked one, you would definitely like the other!
Similar working woman and boss drama. Though the heroine in MS is emotionally tougher. Hapi Mari has a marriage based plot, MS has fantasy.
Poor Sumi Kitamura… Her irresponsible older brother Eisuke keeps bringing home orphans for her to take care of even though they can barely afford their own basic needs! Just when Sumi's financial problems become dire, wealthy Soichiro Ashida enters her life with a bizarre proposition: he'll provide her with the money she so desperately needs if she agrees to marry him. But can Sumi fool high society into thinking she's a proper lady? Moreover, is it worth giving up everything for this sham of a marriage?
The reason why these two manga are similar is because both deal with a female who is entering a marriage deal with a male because of her money issues/poor issues and tada~ theres the similarity
I like how at the begainning both man what marriage for money but in the end they came to love the woman in the story whole heartly.