the book "hindu female deities as a resource for contemporary rediscovery of the goddess" by gross rita.m, 1989, says:even in the practice of homa (ritual involving fire, and offerings to fire), every mantra or shloka is addressed to swaha, the wife of agni, instead of agni himself. devi bhagavata purana: 9.43, says that all requests to agni had to be made through his wife only:this aspect of swaha as agni's wife is mentioned in mahabharata, brahmavantara purana, bhagavatha purana as various hymns.