Go and get a second opinion and a third and a fourth if you have too.

It may be the dr is right, but it is also equally like that he isn't. get more opinions on the matter so you can feel confident that the opinion is based on factual evidence rather then just one person.

I had bad 3rd degree tearing with the first and barely even any gazes with the 2nd and third. I am not entirely sure of the impact of 4th degree tearing and scaring, but find it hard to believe it would automatically just rule out vaginal birthing forever more. Having said that, if this is the case at least you will feel better about having a c-section if you have no doubt that it is the best method for you.