Koushi Inuzuka wants to be a prosecutor. He has excellent grades, good morals and is very popular. However, his father is a talented martial artist who wants Koushi to follow in his footsteps, and he is hiding an important secret! When Koushi was younger, he was betrothed to the daughter of his father’s rival: Momoko, the strongest bride in the world! She’s cute, devoted, and a talented martial artist; and with Koushi’s father’s blessing, she is now the newest member of the Inuzuka household – much to Koushi’s dismay! Now, all Koushi wants to do is live a normal life and become a great prosecutor… but with two martial artists to deal with, can he keep his path – and sanity – intact?
If you liked Eri from Fujimura-kun Mates or Momoko from Sumomomo Momomo, then be sure to check the other manga as well, because those two characters are quite similar. Both of them are rather adorable umm... perverts who are set on reducing birth decline with a guy who not only is uninterested, but also finds the girl to be a great annoyance.
This recommendation is based just on one thing: both Fujimura and Kyon mastered the secret art of tsukkomi. If one of those guys managed to make you laugh, it's safe to assume the other one will do so as well.
If you can't get enough of Eri, you could try reading Trinity Seven. It featurs a character named Arin who is very similar to Eri (though not as awesome). It should be noted that the protagonist of Trinity Seven, unlike Fujimura, doesn't seem to be bothered by having a harem, in fact he seems to enjoy the company of all those girls very much.
Daichi Shinigawa is a typical delinquent who wants nothing to do with high school. However, bespectacled Hana Adachi, the class representative, will do anything in her power to make sure Daichi participates in whatever events the school has to offer. If she has to surprise him in the boy's bathroom to get him to go on the school field trip, so be it! Daichi is confused as to why a class rep would care so much about a troublemaker like him; what could be the reason behind her actions?
Yankee-kun to Megane-chan has similar plot to Fujimura-kun Mates, that is a delinqent getting dragged into school life by a not so normal girl. However the humor is way less over the top and there is way less harem there. Still Yankee-kun to Megane-chan is a good title, so if you liked Fujimura-kun Mates, you should give Yankee-kun to Megane-chan a try.