Complex sentence: Seretse would not budge in his desire to marry Ruth (which he did while exiled in Britain in 1948), and tribal opinion about the marriage basically split evenly along demographic lines-older people went with Tshekedi, the younger with Seretse.
Split into simpler sentences: Seretse would not budge in his desire to marry Ruth, and he did, while exiled in Britain in 1948. Tribal opinion about the marriage basically split evenly along demographic lines-older people went with Tshekedi, the younger with Seretse.