Severed Head is essentially a heady, intellectual, painfully English version of Bob & Carol & Ted & Alice. Murdoch presents, as she always does, inordinately interesting and intelligent characters so above you and I in all matters with the exception of their inability NOT to be driven insane by love.
Martin has both a mistress and a wife he loves. Much to Martin's surprise, his wife tells him that she is leaving him for her therapist. Martin is devastated. But why? Should he not just build a new life with his mistress? Of course not. Because love is not about the other, but about the elevation of the self. And romantic happiness, in Murdoch's world, is entirely rooted in the self. Happiness comes not from what two people can give to one another, but from something far more pessimistic. It's a blunt but not unrealistic view of the reality of relationships.
Love is a complex and semi-diabolical landscape in Murdoch's work. The blunt mechanics of sex are almost entirely absent in her stories - even the suggestion of it is hard to extract. But the all encompassing obsessiveness which love unwittingly inflicts on humanity pervades her stories and nearly derails the lives of her characters. The reader, at least this one, is always left with a tremendous sense of unease. I love her work - being an unabashed anglophile helps.