I really feel for your situation. I am pregnant with my 5th baby and will be having my 5th c-section in 7 years. I am scared.

Like you, my doctor told me the “risks” involved with having multiple c-sections, especially so close together… and especially because with my last baby, as the doctor was stitching up my uterus, it tore because it was so thin. She had a hard time stitching it because of that.
We didn’t really plan on having anymore simply because of that, but we kept it in God’s hands, fully believing that if He wanted to bless us with another little one, He would also watch over me and baby during these 9 months. So, following the sympto-thermal method, we abstained at the first sign of fertility (for me this was fertile-like mucus). We then waited until we saw my temps rise. BUT, instead of waiting for 3 high temps per the rules of the sympto-thermal method, we decided to put it in God’s hands on the day immediately following the temp rise and “abandoned the method.”

Despite the statistical unlikeliness of conceiving on the day after a temp rise (still very possible, mind you, but statistically less likely) we conceived our baby #5.
And this has been my easiest, most blessed pregnancy yet. I worried early on about losing the little one because of some spotting and my heart was just breaking at the thought. We’d already fallen in love with our little peanut! And so again, we return to putting it in God’s hands. My first appointment is Monday.
Anyway… long story short (too late!) I understand your situation. After this baby, DH and I plan to continue to use NFP and trust in God. And follow the actual rules better.

While a tubal ligation would make things so much “easier” in some respects, I think it would take an emotional toll on us knowing that we explicitly disobeyed the Church. And even more so, I feel like it would be a slap in the face to God. As if we’re saying “We don’t trust you and don’t believe that you know what’s best for us, so forget you!”

I just couldn’t do it.
I encourage you to take a course in NFP and learn the rules inside and out. Following the rules to the particular method you choose gives you like 99.9% chance of avoiding another pregnancy. I figure if you get pregnant literally out of that .1%, God REALLY wanted you to have that baby!
Sorry for being so long-winded! I hope and pray that you find peace in your situation.