Complex sentence: Her second marriage was to former politician and columnist Jim Sillars, whom she married in 1981, who went on to win the 1988 Glasgow Govan by-election for the SNP.
Split into simpler sentences: Her second marriage was to former politician and columnist Jim Sillars, who she married in 1981. Sillars went on to win the 1988 Glasgow Govan by-election for the SNP.