After after a thorough analysis of all the prices, the best opion for you and your wife for one way and back to zermatt from 04/02/2023 til 04/07/2023 will be the Saver Day Pass. With the Saver Day Pass you can travel throughout Switzerland for a day on all routes in the GA area from as little as CHF 29 with a Half Fare Travelcard and from CHF 52 without a Half Fare Travelcard.
We also checked the prices wirth the Half Fare Card and the normal Point to Point ticket, they are higher priced. You can find the Saver Day Pass and all the prices at our home page under the following link: Saver Day Pass – book earlier, travel cheaper | SBB
Just be carefull because the Saver Passes and Saver Ticket are limited.