Yeah, not everyone can tolerate Finasteride. Most people will have no problem with it, but some do experience mild sexual side effects like softer erections, loss of libido, and watery semen.
Quite often, thse sides will diminish with continued use, but if not, you can always hop off the drug.
Personally, if I did not use Fin, I would use topical spiro. It is the most battle-tested topical for fighting DHT that we currently have readily available. The downfall is that it can often give off an unpleasant odor, and because it comes in a cream it can be difficult to apply to areas with existing hair.