If you intentionally stab yourself, will you die? You could. If you act time after the fact, you may live, stabilize, heal, and recover. You will likely bear the scar; may have lingering pain; and will certainly regret doing it.

If you intentionally cheat, would your partner leave you? They could. They might forgive you if you apologize, show true regret, understanding of what you did wrong and why you did it and why you will never do it again. The relationship will still have been much better off if you had never cheated.

Sin is spiritual injury. You betray the trust and love and your connection with Christ. Regeneration is possible and God is inhumanly patience and merciful - but far from fear of hell, the fruits of the Spirit alone that you gain by steady devotion are worth never straying in the first place.