Tamagotchi Marriage

I’ve read how the marriage works with the egg on the App, but nothing says what happens to the parents? 

I’ve found once you’ve connected to the app you can send your Tama back to the Tamagotchi and still have the same Tama as your avatar on the app. Can marriage work like this or does your Tama have to be actively away from the Tamagotchi at the time? If you do successfully marry, how do you return your Tama+their Partner if that partner was found on the app? I don’t want to accidentally loose my Main original Tamagotchi through a glitch or something.

When you send your tamagotchi to the app, you are able to bring it back to your device without the app (in the event that the app crashes) by pressing "C" and choosing the return option. So your tama will be safe if you choose to send it away.

When you get an egg, you'll be asked to connect your device to the app and the egg will be transferred back onto your device.

Another tip, if someone proposes to you, but you don't want their genes, you can click accept without transferring the egg onto your device so that they can get the genes and you can continue searching for a partner you like.