I’ve asked for forgiveness for my fornication, but today I did it again. I’m not convinced God will forgive me again

Answer:

I take it that you have been having sex with a woman who is not the woman you are engaged to marry.

God forgives sins when they are truly repented of. It doesn't matter if the sin is repeated. "And if he sins against you seven times in a day, and seven times in a day returns to you, saying, 'I repent,' you shall forgive him" (Luke 17:4). What matters is that you are against the sin and are determined not to repeat the sin. In other words, that you have made a radical change in your views and behavior. "For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death. For observe this very thing, that you sorrowed in a godly manner: What diligence it produced in you, what clearing of yourselves, what indignation, what fear, what vehement desire, what zeal, what vindication! In all things you proved yourselves to be clear in this matter" (II Corinthians 7:9-10).

Since the problem of forgiveness does not lay with God's ability and willingness to forgive, I suspect the real problem is that because you've repeated your sin that you are no longer confident that you have changed. "What shall we say then? Shall we continue in sin that grace may abound? Certainly not! How shall we who died to sin live any longer in it?" (Romans 6:1-2).

I don't know why this sin was repeated. I don't know what you did or did not do to make sure this sin would be less likely to be repeated. But I can tell you that you need to pick yourself up and redouble your efforts in battling this sin. If you don't, it is going to destroy your marriage and you.