I think 'it's okay, that's love' has a rather mature outlook on love, it's my favorite romance drama. It takes a while for things to develop, but the deep affection they have for each other, how to say... I don't think I've seen other dramas where I could feel it that intensely. Even Healer, Secret Garden and Fated to Love You, cannot compare in my opinion, because they seem shallow in comparison (puppy love, or love based purely on dependency for another person...). However, I am not sure if it's what you're looking for, because while they do have passionate moments as well, it is not your typical RomCom. Either way, I'd recommend it with all my heart, it's an amazing drama!