Infertitility is a foolish marriage viabilty litmus test.
Potential for procreation is the core. Even after childbearing years God has blessed couples with children.
the evolutionary dead end of homosexuality has ZERO potential for procreation ergo no marriage impossible by definition
Man and Woman He created them: a Theology of the Body, will answer remaining questions. DO NOT bother with summarised versions of the text as it is available in English already.