I never found it particularly difficult to avoid unwanted relationships in BioWare games; in fact, I had the opposite problem with Juhani.
Ah, the OG catgirl romance, you have good taste, sir. Though I have always went for Carth for the rare fem!PC playthroughs of that game, because he might be a knock-off, inexplicably straight-laced Han Solo, but he is
my knock-off, inexplicably straight laced Han Solo, damn it. Going straight for a mourning, revenge fueled widower did feel pretty awkward, tho, especially so soon after playing BG2 and being torn up about pursuing Jaheira. At least we hadn't been adventure buddies with Carth and his wife for a whole previous game to make it extra uncomfortable.
Going back to the main topic of the thread, KotoR 1's Bastilla should definitely count: her romance is smacked right on top of the main plot and even being a dark side ass didn't help discourage her tsundere thirst for male PC's D, it just led to her turning into a yandere later down the line. Still love her to bits. And I guess in general I've never had a truly grating or frustrating experiences with in-game romances, at worst they were unintentionally hilarious or forgettable.
No comment on other RPGs, since none of the other ones I've played through have romance options.
Were they Obsidian games, by any chance? Cause seem to have at some point made a conscious decision to move in the opposite direction to Bioware, creating games that are progressively more devoid of any notion of PC-NPC romance.