“When Christ died for you sins, how many of them were future?”
Are you telling us that because Christ died on the cross one time, that anything you do in the future from the point you “believe and be saved” is of no consequence to your soul?
2 different issues are being discussed in this question.
Forgiveness is not the same as Redemption.
Forgiveness occurs based upon a righteous and just judgment.
The Cross was all JUDGMENT, not Forgiveness.
Just as Adam sinned once, resulting in condemnation of all, Christ's work on the Cross, resulted in one Judgment, providing the Redemption for all.
That is why in a moment, one can have faith alone in Christ alone and be saved by Him immediately.
After that initial salvation, is it possible to sin again? Sure, we are all sinners and all carry a scarred soul, an old man, an old sin nature, which we find repetitively rears his ugly head and pulls us out of fellowship with Him, grieving the Holy Spirit when we sin.
Post salvation sin scars our soul, so by all means it is being communicated in Scripture that there are consequences to sin after salvation.
Nobody is getting away with anything by sinning after salvation, we simply place ourselves in the wrong place at the wrong time to perform as He has intended for us in His Plan. We simply fail to perform so as to run the race the best we can, and leave an inheritance reward on the shelf which He had predestined from eternity past in heaven to award us eternally.