However, this word also is used figuratively for apostasy. He likens his relationship with his people to the intimacy of a marriage. When his chosen ones place their affections on idols, he charges them with committing spiritual adultery. You are like an unfaithful wife who loves her husband's enemies. True marriage is more than a sexual union, a physical bonding, even though we sometimes seem to treat it that way.
True marriage is in essence a love relationship.
Outside of that framework it is not the real thing. The way the simplistic formula is so often applied, one could assume that the first vow in the marriage ceremony is a pledge not to get into the wrong bed. The first pledge is to love , and the other follows naturally. Nothing will keep a marriage from falling into physical adultery more surely than having abiding love one for the other. In fact, before physical adultery takes place, some spiritual adultery must be indulged in.