I don't really understand this 'getting married for spiritual progress'. If they wanna progress together "spiritually" they can just stay together, I don't think they have to be married for that.
I can stay with a bibi for spiritual reasons BUT i don't have to be married. No physical relation exists but they are together. I am sure world would point fingers BUT the bibi and the guy know what they are doing, Guru Ji knows what they are doing..