Isn't Jesus being declared as God adultery, and isn't the cross an idol?

No and no

Loving God, is different than loving a husband or wife. The love of God is greater than the love of a human being.

The cross is a symbol. To be an idol, you would have to worship the cross and acknowledge it as more important than God himself.

No and no. If you love Jesus you love God as well. They are all one person. The Holy Spirt Jesus and the Father. The Holy Trinity. (Not to rip off Bluu but...) Bluu is correct The cross is not an idol it is in fact a symbol.

Saul was a high ranking Jewish priest who was killing Christians because they were worshiping Jesus, and calling Him the Messiah, and that He was God in the Flesh.

So, on a road to Damascus, Saul was blinded by a very bright light; and he heard this voice saying" Saul' why are you persecuting ME!"
He knew that was the real Living God speaking to him. Saul followed the Lords instructions, because he was aslo blinded, and had like a cataract on both eys.

Saul was led to a street called straight, for three day he was blind, a man named Ananias who was a disciple placed hands on him. When he did, fish like scales came off him , and Saul was filled with the Holy Spirit. ( ACTS 9: 1-31)
He then begin to preach in the synagogues that Jesus was the Son of GOD. Later God gave him a new name. Paul. Which became the Apostle Paul who wrote Romans in the new Testament along with other books too.

So to your question, regarding Jesus who He is," The Farther and I are one "
and Saul found out, he saw the light! and the cross is a Christian symbol , of what he did on the cross, ( to take away all sin) and how we should live are lives like Him. Not a idol!

So I hope you you accept the living God in your heart; Jesus.! Ask him Him to come in and change you from the inside out. To accept Him as your Lord and Savior. Because our God is Mighty to Save, He can move the mountains!

no and no God and Jesus are the same and the cross is a symbol

Yes and yes.