This one is still shrouded in a bit of mystery. But what is known is that Rik met former girlfriend (and Young Ones co-writer) Lise Meyer while at University. They dated for several years and ended up living together.
In 1981, Rik met Barbara Robbin (now his wife) at BBC Glasgow. Barbara was a makeup artist there during his stint on A Kick Up the Eighties as "Kevin Turvey". Rik has said in recent years that when he saw Barbara, he knew that she was "the one" for him.
Rik started seeing Barbara on the sly and the affair was kept a secret. Things went on this way for five years (yes, you read that number correctly!).
In 1985 both women became pregnant by Rik. Upon hearing Barbara was pregnant, Rik immediately slipped off to run away with her -- they flew to Barbados and got married.
It's not known if Rik knew of Lise's pregnancy at the time, but Lise's pregnancy ended in miscarriage. More details are not known.
Rik claims he and Lise put the past behind them and became friends two years after these events.
The two best news stories for more information on this are A Joker Who Scorns His Critics and Rik Admits: 'I Dumped Angus's Girl'.