Text and Voice Messages Transfered to CPU

I would like to get messages sent between myself and my partner onto the computer. I would like all texts, but it's more about the voice memos; That's the predominant way we communicate. I have the voice memos I sent, but in order for me to listen in order I would have had to save every one of his as soon as he sent it. I'm writing a book on relationships, yes, he is aware, and I am using our real-life story, so this is really important data.

I have tried backups and I've tried a lot of the apps that can capture the text messages. The problem I'm having is a lot of those options only allow me to read messages. I need to be able to listen.

Thank you in advance.