Mayamia, I'm glad you found your way here. I'm going to answer your question about grieving in the context of your comment about going back to church.
Do you know Psalm 22? The one that Jesus quoted on the cross. The beginning is devastating. My God, my God, why have you forsaken me? . . . I am a worm and not a man, scorned by everyone, despised by the people. The psalmist goes on and on, thoroughly exploring just how awful his life is. But interspersed from his exploration of just how awful his own life is are affirmations and statements about how good God is: Yet you are holy, You who are enthroned upon the praises of Israel. And remembering that God is his creator: Yet You are He who brougth me forth from the womb; You made me trust when upon my mother's breasts.
For me this is a model of despair, when I am despairing. To thoroughly explore all the aspects of the despair, just how awful things are, to give words and voice to all of it. Then to intentionally change my perspective to consider the character of God: goodness, majesty, widsom, mercy, power, beauty, whatever part of God I need on that day. And to remember that as my creator, he cares for me, like a mother cares for her baby. A baby doesn't do anything to earn the mother's love and there is nothing a baby can do to make the mother not love them. Like that, that is how you are cared for and loved. Sometimes it takes me a long, long, long walk in the woods and sometimes more than a day or two before this works, but it works, reliably, and the more healed I am the more I have to offer to the people I care for, including the people I have hurt.
Also, please consider offering your disabled husband the dignity of the truth of the marriage and the agency to decide whether he would like to remain married to you or to rely on the services that are provided through government or charity (not ideal, I know, but also not nothing), or his children. There is so much agency taken away from people who rely on others to care for them. Betrayed spouses often talk about the loss of agency as one of the most damaging parts. The more you can give back, the better. I realize this is an extremely complicated situation, but please consider it.
I'll pray for you mayamia, your name reminds me of the name of my favorite poster (Maia), a beloved friend who died a few years ago. Read through Maia's Survival Guide if you need help on detaching from the relationship that you formed with the AP.