how to make no-sex marriage or open relationship marriage

How to make no-sex marriage or if not at least open relationship marriage?

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(context :

i, 35male, 've been meeting a woman of same age, christian, somewhat masculine(literally from her look to character), outgoing, active.

idk her sex drive but i got none. My purpose meeting her is everything except physical interaction. i believe building life together works better for both, but i want to skip sexual part and if this doesn't work i want to just let her have casual guy friend who can satisfy her desire. As this is sensitive topic to handle, i'm still reserved to openly discuss it with her)