I'm so sorry about your injuries during childbirth. This happened after you were married, so I see it as covered under the "for better or for worse" so it gives him no excuse to cheat.
If this can't be healed, can you provide him with other types of sexual activity - say oral - not as a chore, but as a "gift" to a man you love. At the same time he should do everything he can for the wife he loves.
The traumatic birth happened during my first marriage, this is my second marriage. My current/second husband knew about it before we married, but after we got engaged. He always had an inkling something was wrong but didn't really know what it was. He thought I was just tough to please or had some sort of sexual hangup.
I met my 1st husband in ’96, when I was 15.
I married my 1st husband in 2002, at 21.
I had my 1st daughter with my ex-husband in 2003, at 22.
Following that child birth is when my sexual problems started
I divorced my 1st husband in 2005 (sex being the main reason), at 24.
I started dating again in 2009, at 28.
I met my 2nd husband in 2012, at 31 - he was 34.
I married my 2nd husband in 2013, we had been together for 16 months, engaged 2 months
We had a daughter together in 2015, via planned c-section so things didn't get any worse - if that's possible
So he knew about it before we married, but not until we were engaged. We were only engaged for 2 months before we married. He didn't have a ton of time to change his mind, maybe he would had if we had a longer engagement.