Hello and welcome to the forum. So sorry to hear about your situation. I do recommend working with a doctor. If the first one you obtained an opinion from is something you are unable to fully trust, a second opinion is never a bad idea. This is a very good question as the statistic is 80 percent of those with a meniscus tear do not need surgery.
I do understand your concern as that is almost all of your meniscus, however, it is still not all. This would then be a parietal meniscus removal and that has a better long term outcome for your lifestyle and comfort than a full meniscus removal. A partial removal of meniscus surgery can be very effective. Full removal possibly could affect stability of the knee, future osteoarthritis risk increases, as well as degeneration of the knee joint. With either a partial or whole removal, care needs to be taken of the nerves passing through the knee.
Living with the injury may not be feasible in your case with such a bad tear and recovery very well may require surgery, unfortunately. But do seek a second opinion to feel more comfortable with your choice. Let us know what you think or decide to do.
Hi worrywart, we sure hope you come back and update us. We'll try to help any way we can.