I remember a while back someone asked a question about why certain games attracted ire for having the option to pursue homosexual relationships and why others that had the same feature barely got any controversy, so I'll post my answer from there: http://www.escapistmagazine.com/forums/read/9.399700-Why-was-there-no-uproar-about-same-sex-relations-in-Skyrim-or-the-Fable-series#16403957
The basic conceit comes down to three particular aspects: the first is how pronounced the feature is in the marketing for the game. Games such as Skyrim or Fable mostly focused on the none-relationship aspects, and the few times it did it was more to show that a relationship feature was in place, they didn't really make a big deal or production over the fact you could have same-sex relationships, while things such as Dragon Age 2 and Mass Effect 3 made such a big deal about it, implying that it was more of an integral and necessary feature rather than just something that's there as an option. The Sims has always seemed to go down this path, in which I've never seen a Sims game make a big deal out of having Sims of the same-sex pursue each other (when I say big deal, I mean the marketing didn't call attention to that one fact as if it were a new mechanic players were expected to employ)
The second aspect was that in most other games with relationship options, those relationships usually amounted to nothing. Fable and Skyrim's relationships were more for window dressing than anything else, and if it was one of those few times it resulted in being given something, it becomes easier to identify that relationship as one out of the necessity of an item rather than a reflection of the player's personality. It goes without saying that the relationships in the BioWare games were made more important due to their emotional resonance both with the character and the player, and as such are more reflective of the player's personality as opposed to RANDOM_NAMED_NPC_#4967. It only really becomes an aspect of it's own if the player feels they aren't using every aspect of the game as much as they can, and if that includes pursuing each relationship, sooner or later the same-sex ones are going to crop up, and may make it more of an issue for the players that get uppity about that. The Sims, meanwhile, seems so divorced from the concept of anything particularly special or significant. Sure you can create yourself, but from what I've seen, people treat The Sims less as placing themselves in the world and more acting as a god controlling the actions and environment of the world below them; I'm sure in this instance it really doesn't matter if a same-sex option is a thing.
There's a third aspect, however as someone posted, The Sims may actually fall into the more controversial side of this one, depending on your outlook. This aspect is on how easy it is to fall into same-sex relationships without intending to do so. Skyrim and Fable's romance systems don't really allow for accidental clicks, so if you ended up in a relationship with someone, it's usually because that was your intent; therefore the chances of you falling into a relationship you don't want is pretty much null. In BioWare games it can be considered easier because generally speaking, simply acting nice may convey romantic interests, even if all you were doing was trying to be friendly; it can seem more jarring for a player if it seems to come out of nowhere, and as such may think the game is trying to tell them something about their personality that has less to do with the player's actual personality and more to do with the game's dialogue system. Now, based on what someone said, The Sims may fall into this category, in so much as it's possible to miss-click and have Sims enter a same-sex relationship, but as we discussed in aspect 2, the fact these relationships barely matter and are less a representation of the player than the toys a player simply has around, it probably amounts to very little in terms of controversy, especially since, if nothing else, it can be just as easy to not continue that relationship if you really care, if not just create new characters.
