If an ex-christian does not/did not believe that God came to Earth in the form of Jesus, then they really did not have a Christian belief system to begin with.
Of course there will be mental distress because their views were not of Christianity....in that case, leaving "the belief system" would alleviate the struggle in their mind because they do not feel insync.
Like attracts like.
The difference is that christianity and some other belief systems believe that God's Spirit indwells.....and the person themselves are not gods nor are they themselves the higher power.
Believing that oneself is a god, is of the "man of lawlessness" spirit. "...he sets himself up in God’s temple, proclaiming himself to be God.
2Thessalonians 2:3-4
You and I both know what God's temple is....our bodies.
My thought is that if one believes they are god...they shouldn't really need a support forum....should they?.