Without prayer, fasting, and faith in God, we are powerless over our sɛҳuąƖ urges.
Your post was mostly good, but this is an exaggeration. Perhaps "there are no guarantees" would be true. But powerless? That depends on how much natural virtue we have built up.
There is such a thing as "natural virtue" -- which even pagans can develop.
There is a story about a Catholic writer in the early 1900's who was travelling on a large ship, I forgot where.
He went out on the deck to have his usual cigar, where he met a Muslim man. He made some small talk to the Muslim, something along the lines of, "gotta have my cigar!"
The Muslim replied, "I refrain from tobacco for the love of Allah."
The writer was so taken aback, shocked, and disgusted with himself -- "here's this pagan, with no knowledge of the true Faith, the true God, no help from the Sacraments, never nourished by the Body of Christ and he manages to abstain better than I, who have received much more graces and have more incentive to abstain."
Angry with himself, he cut up the cigar and threw it into the ocean. He decided to give up smoking.
I might have some of the details off, but I remember that story. It's a real lesson about pagans and natural virtue. Sometimes the pagans "show us up" and out-perform us in this or that virtue. Even though they act for purely natural reasons, and we have the motivation of Heaven and the example of all the saints!
St. Paul also discussed this in his Epistles. He spoke about athletes giving up many things, and practicing a lot of mortification, for the sake of a perishable crown -- but we as Catholics work for an imperishable one -- we should be working even harder than those Olympic athletes!
Think of all the liberals and "vegans" who eat no meat ever, not even fish, for years on end -- for the planet, for Mother Earth, to be a good eco-citizen, to be nice to animals, etc.
While some Catholics whine every Friday they can't have meat :)
The list of examples is endless.