I won’t comment in this thread as I believe the issue you bring up is too personal and deserves a personal response. But I’d like to invite you to send me a PM. Here’s why…
My wife and I have three children (plus one in heaven), and a fourth (fifth) on the way - please pray for us. Our eldest child is special-needs. She has an extremely rare chromosomal deletion that has resulted in moderate to severe mental and physical handicaps. She’s 9 years old, but at the cognitive level of a 1 to 2 year old. She’s been on a feeding tube her entire life, but has recently been very serious about taking food by mouth. She’s also completely non-verbal.
My point is, I understand the struggles and anxieties you and your husband are dealing with as individuals and as a couple. Although my wife and I are fortunate enough to be on the same page in these matters and remain open to life, we have similar concerns when it comes to the financial, physical, spiritual, psychological, and emotional strain on us as individuals as well as a couple, and on our family as a whole.
I would join the ranks of folks who are recommending that you talk to a priest about your situation. Although some can be rather insensitive, for the most part they will be very understanding and will want to help you in any way possible. I’d also recommend the two of you find a good support group that you can turn to for encouragement.