Yeah, it was ludicrously forced in its attempt at political correctness. I'm struggling to think of same-race couples at all. Even Donna's fiance in The Runaway Bride was black.
Of the top of my head, series 1:
Rose's parents were both white. In "Rose", Clive and his wife (and children) were white. In "Father's Day", bride and groom were also both white.
"Tooth and Claw" had a white married couple. So had "The Idiot's Lantern". "Love & Monsters" had Elton and Ursula, both white.
The old married lesbian couple in "Gridlock" was also both white. Laszlo and Tallulah in the "Daleks in Manhattan" two-parter were white. In the "Human Nature" two-parter, the humanized white Doctor falls for the white Joan. In "Blink", Larry and Sally are white. The Master's wife in the series 3 finale is also white.
The married couple from "The Unicorn and the Wasp" were white, as were the married couple from "Midnight". Of course, Rose and the half-human Doctor at the end of "Journey's End" are both white.
And, finally, the aforementioned Mickey & Martha scene in "The End of Time".
Also, what sttngfan1701d said.