If it's out of God's will for the relationship and the pain to happen, then it is needless. Just because He will clean up our mistakes, doesn't mean that we should make more of them.
But James 1:17 says "Every good and perfect gift is from above, coming down from the Father of the heavenly lights, who does not change like shifting shadows." If good can come out of the relationship it must be a gift from Him.
So this has become sort of question-answery now and not really consolidated into a complete position. I'll simplify as much as I can.
Everyone is untrustworthy, but trust is required for relationships
God commands us to love (a relationship) everyone
Distrust is an enemy of love and destroys relationships
An enemy of love is an enemy of God
Distrust is an enemy of God.
I am incapable of trusting completely
I should seek to be a friend of God
An enemy is not a friend
I should seek to trust completely because distrust is an enemy of God
Every good and perfect thing comes from God
God's will is perfect
Ignoring our fears and doubts and embracing God's will is perfection
Distrust increases fear and doubt and makes them harder to ignore
Distrust makes it more difficult to embrace God's will
Distrust deviates from perfection
Imperfect people should seek perfection
I am not perfect
I should seek to root out all distrust
God presents specific commands about who to exclude from the church
None of the reasons relate to someone hurting my feelings
I should seek to live my life based on God's Word to the best of my ability
Distrust as a result of hurt feelings is not a Biblical principle
I should seek to not distrust people who hurt my feelings
Now can I say that I trust perfectly? Far from it! But when we embrace distrust and call it acceptable, I truly think it is, or so nearly so, sin(see above) that it should be treated as such.