The campaign I'm running now is highly social, and all my players really got into building non-combat oriented characters (except, ironically, my husband). Some players made it clear that they did want romance and/or sex to be a major part of the game for them, and others made it clear that they were just not comfortable going there. After a year and a half of play this is how things stand:
The Paladin : No significant others or one-night-stands, totally devoted to his religion and his mission. Player has fun glowering at everyone else when they get "frisky" and acting indignant when NPCs try to flirt (or cop a feel).
The Rogue : Played as a Tinker rather than a Thief. One "meaningful one-night-stand", mostly played as too wrapped up in his science and his bussiness to be interested in romance, but if the right young gnome comes along....
The Wizard/Rogue/Mistress of Flowers : Played as the girl who came from a waaayyy too strict family who came to the Big City and went a bit wild. Took up with an NPC prince who might as well of had "tall, dark and tourtured" branded on his forhead. Enjoys playing the whole thing for laughs, will never live down the random die roll that had her character heading upstairs with the prince and a halfling slave girl during a very interesting party. Actual sex handled as a simple statement of "I spend the night", with an occasional die roll to see who impresses whom the most.
The Bard: Oddly enough the Bard has seen about as much action as the Paladin, though considerably more temptation is placed in his path. Played as too devoted to his Art to be distracted by mere women, though he does have a soft spot for damsels in need of rescue. Adamantly turned down a political marriage, uses his high Diplomacy to gently deflect all attempts at flirtation.
The Psion/Rogue: Played as a scholar/rebel. Lost his virginity at the most expensive Pleasure House in the city, very slowly developing a friendhsip with an independent commoner womean while his NPC grandmother tries to wheedle him into an arranged political match.
The Sorcerer: This player dived in to the whole romance thing and now is a member of a threesome, all of whom are deeply in love with each other. Since most of this took place "behind the scenes" anyway it was mainly handled over email. This allowed us to go into a lot of details about emotions and flirtation, but things always ended with the camera panning away artfully. We did go to places that we simply would not have gone in front if the group at a table though.
I realised pretty quickly that any in-game sex at the the table was going to end up being played for laughs no matter what, so I went with that for the group as a whole, and deal with anything of serious emotional content via email, for the players who want to explore that aspect. Works for our group.