Just looked at the character studies for the various companions in Dragon Age (again, now I know more) and... um... *snicker* You get glimpses of the sex scenes for Morrigan and Leliana (with a male), and a really short bit of Zevran (with a red headed female elf. go figure) but not Alistair.
Poor, dear Alistair.
Let me comfort you.
Wait.. what was I talking about, again?