The text do not differ on the indissolubility of marriage.

The word translated “sexual immorality” or adultery is the Greek “porneia”. The Arndt, Gingrich, and Danker lexicon states that the word refers to “prostitution, unchastity, fornication, of every kind of unlawful sexual intercourse.”  This would include homosexuality, as an example.

Resolving this fully is well outside the scope of a simple discussion, but the Catholic interpretation of it is that it describes something which we would consider today a cause for a declaration of nullity, a radical inability to achieve and/or intention against at the point of marriage to monogamy.