I'm mom of a child with numerous permanent disabilities. He has a trach, ventilator, feeding tube, and the list goes on. He is also nonverbal. He is not a "vegetable" as many have referenced (a term I actually find kinda offensive), as he is full of personality/joy and loves to play with baby toys, but he is definitely my "forever baby" and I will care for him as long as he lives.
That being said, he didn't choose this life, and there is NOTHING easy about it for him OR myself. I love him more than anything else in this world and I accept him 100% just as he is, but do you know how hard it is for me knowing I'll never have a normal conversation with him or do the "normal" parent things?
Please think long and hard before putting this responsibility on a partner. Even if she willingly agrees, she has no idea what she's truly in for unless she's been a caregiver to someone with disabilities for a long time. I can assure you it's nothing like taking care of a typical, healthy child.
I could go on but honestly you seem pretty determined to do what you want to do regardless of the advice you are getting. If you have any questions, though, feel free to ask. I have more experience in this arena than most because taking care of a special needs child is my whole life.