If you don't mind a few other suggestions:
Always Sometimes Monsters (you can choose to play as a female, and have a female love interest)
http://store.steampowered.com/app/274310/
Choice of Deathless (a text game, but you can play as female, and romance two females)
http://store.steampowered.com/app/318310/
I also don't know if you want to include Sims 3, but it does allow same-sex marriages.
There was a game recently released called Enola. I haven't played it myself, but you play as the titular character, Enola, and "you must survive a macabre world conjured up by the tortured memories of her love, Angelica"
http://store.steampowered.com/app/263520/
Finally, there is The Yawhg. You don't have control of romances, but some of the random encounters, it is possible for your character to get intimate with females (like an orc, or a prostitute). This may not fit the criteria of your list.
http://store.steampowered.com/app/269030/
Your list included Fallout 2, and Fallout 3. You might wish to add Fallout New Vegas. While there isn't romances per se, you can flirt with females, and lesbians do exist in game (Veronica comes to mind), not to mention the Cherchez la femme Perk gives a few interesting dialogue options with females in game.
You may wish to keep an eye out for Roommates by Winter Wolves Game. While it isn't officially out on Steam yet, I know it passed Greenlight

Something that may be a bit of a stretch for your list, but you may look at Tropico 4 and Tropico 5. You can make a female President, and there is an edict which allows for Same-Sex marriages. Not that your character engages in this herself...