Philogamy has been used in various books, therefore philogamist is the answer.
-neologism derived from:
phil-/philo-(Forming compound words indicating "fondness for", "favor of", "respect for".)
-gamy (Used to form nouns describing forms of marriage) (Wiktionary)
" 'philogamy' (the positive attitude toward marriage encouraged by the church)"
"The State has no right to condemn these individuals to solitude and unhappiness, or to deny them civil recognition of spiritual generation, which is not less real than the corporeal, and is a result of philogamy."
"I would define faithfulness to such mobile demes as philogamy."
"We shall call this defence of marriage 'philogamy', referring to Erasmus' Virgo misogamos (the girl who was opposed to marriage), the title of one of the dialogues in his Colloquia familiaria. "
"Luther started noisily the trend to philogamy; he was personally quite direct in stating that he enjoyed sex with his wife. "
"The misogamy which had typified the Church's approach to family life was now contested by a new philogamy."
"Though overstated the argument has real merit, and is extremely useful for its discussion of the place of philogyny and philogamy in anti-monastic propaganda."
"Prologue mocks philogamy with a sardonic flair more characteristic of a witty poet than of any pilgrim-narrator."
" ' "Acrasial Philogamy?" Brother Edward, what is that?' 'That,' replied Edward, 'is an incurable malady to which young persons are subject.' "