Past failure should not keep you from God’s best. If you have confessed sin to God, He has forgiven you.

If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness. (1 John 1:9, NIV) 

God’s promise of a life plan that is “good, pleasing, and perfect” is made to those who have sinned in the past and need transformation.

Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is—his good, pleasing and perfect will. (Romans 12:2, NIV)

However, you need to be honest with yourself about the past. You also need to be honest about the past with your potential spouse.   Good communication starts with honesty. Mutual respect requires that a potential spouse be given the opportunity to respond to you sincerely, based on the truth.

Don’t allow past failure to make you think of yourself as damaged goods. If you recognize that God has cleansed you from the past, you can maintain purity and self-respect as you approach the future.