Futari Ecchi

Both are based on "educational" works who tries to give sexuals lessons to those who ... Oh, lame excuse to sell. The animated adaptations follows a charismatic, inexperienced and shy couple: in "30-sai" they are still trying to get together, with the help of their clumsy god friends; meanwhile, "Futari Ecchi" starts by the marriage, but its protagonists are equally or even more naive and lost. Different environments, similar situations. The two recount with pleasant mood the difficulties and the steps that these couples give in direction to love, in a way that does not abandon its "didactic" origin. "Futari Ecchi" stands out for having a more mature story, while "30-sai" constantly loses himself in questionable and embarrassing scenes. read more 

Both are ecchi comedies about middle-age couples trying to improve their intimate life. 

Both shows deal with old adults who've had little experience in love, starting to learn about romance and sex. They both also offer some sexual education value (and are both wholesome romances if you're looking for that)