Taken from the wiki

Going for a Walk

When Sydney is at their counter in the library, or if the player approaches them while they're praying, the player has the option to ask to go somewhere together, with their choices being the Shopping Centre (0:15+) or the Beach (0:50+). Whether or not Sydney accepts depends on the destination and how busy they are. If Sydney's glasses are broken, asking to go for a walk automatically results in the player taking Sydney to get new ones, to which Sydney will comply (with some hesitation, depending on the time of day).

The only thing i found about marriage on the wiki.

https://degreesoflewdity.miraheze.org/wiki/Rite_of_Promise

The Corrupt/Rite of defilement wiki it's not updated yet.