As noted above, this is possible now by marking the "X is the spouse" checkbox. This adds the new record as a non-constituent record.

Is there a way to add spouse without creating a record in NXT? We don't want spouses taking up limited records when we do not contact name. We just simply need their names.

This should be much easier than the way it is set up right now. Not intuitive at all.

You actually can do this currently, but it's a little labor intensive. You just have to go down to Relationships and add the relationship, and then click the "X is the spouse" checkbox.