In case of any marital issue it is always better to discuss with spouse and try to resolve the issue. But if you have already tried to resolve the issue in the past 3 years of suffering then it is always better to part your ways.
But certainly in any circumstances, attempt to suicide is not a wise way. You should proceed with the divorce process. After filing a divorce notice you and your wife would have to attend sessions with marriage counselors. In many cases the discrepancy between husband and wife is resolved with suggestions from these counsellors associated with the family court.
If even the counselling sessions do not succeed in saving the relationship, then the actual process of divorce starts in the family court. The process of divorce will be better handled with a professional lawyer. The duration of the case may vary depending upon alimony requirements, proofs of claims from both sides, children's custody and maintenance claims, claims on property, etc. Finally, at the time of divorce grant, it is essential to have at least 1 year separation. Hence, even after giving divorce notice, minimum 1 year you should be ready to face the case hearings.
Last but not the least, I will suggest you to concentrate on your personal well being and spiritual development. Suicide is never a correct way to handle pressure and stress in life. You should try to find out ways to handle your stress because during the divorce case and in life after divorce you need to keep yourself strong and stress free. You should attempt to learn meditation and some self retrospection techniques.
Life is God's Gift !! Appreciate Life !! Thank you Universe !!