"Is it God's will or my own desires?"
I don't think these are mutually exclusive. If your desires are to experience holiness, grow in Christ, and fulfill your purpose in life, then it is natural that God would use your intellectual and spiritual curiosities to lead you to Orthodoxy. Do not feel guilty for being drawn to Christian depth and Holy Mystery!
The marriage issue is tough. I can relate, because my wife has followed me into Orthodoxy with much reluctance. But she is coming to understand the Faith more and more, and we rarely argue about it these days. You are absolutely right that God ordains marriage; and we know that the Scripture says, "What God has joined together let no man tear assunder." [St. Mark 10:9] But Our Lord also told us He came "not to bring peace, but a sword... a man's enemies will be those of his own household." [St. Matthew 10:34, 36]
Commentary from The Orthodox Study Bible states:
"To carry his cross, a true disciple must be ready, if necessary, to sacrifice even family relationships." (p. 1286)
"There are two kinds of peace. False peace is a shallow harmony that results from ignoring issues of truth. Genuine peace is reconciliation to God through faith in Christ and surrender to truth. Genuine peace has division as a byproduct because not everyone wants truth. In the fallen world, divisions are necessary for truth to be manifest." (p. 1393)
I really believe that God in His mercy will preserve and bless marriages that struggle through these issues. As long as you follow Christ and His Church in sincerity and truth, then you will face both tremendous adversities and tremendous blessings. Love Christ and love your wife, and God will honor that. But truly loving Christ and truly loving our spouse are no easy things.
"Lord have mercy."