My main contention is that if you don't make companions player-sexual, then you end up with a situation like Kingmaker presented, where the game designers created:
1 heterosexual boy,
1 heterosexual girl,
1 bisexual male-female couple
1 bisexual pair of twin sisters

A whole bunch of other very nice companions that would have been excellent for romance but were not options (Ekun, Linzi, even Jubi if that's your thing... I'll probably pass on Nok-nok though).

But, the result was actually that, if you were playing a homosexual male, you had one single romance option available to you, and that one only if you were comfortable breaking him up with his current (female) partner. Heterosexual female characters had 2 possible options only (again, one of which involves breaking up the male from his current partner), while heterosexual male PCs had 5 options, and homosexual females had 4 (one involving required relationship breaking). It ended up being deeply dissatisfying, *despite* the game designers going to great lengths to try to include NPC characters of varied and different tastes and preferences. You simply can't cater to a fair spread of experience and options for everyone if you hard lock the romance options to pre-fixed sexualities.