I agree with Summerleaze above.
If you have a boar neutered then his chances of finding happiness, either with a sow or another boar, are much more likely.
In my experience, neutered boars are more docile and acceptable. Most piggies are social animals and need company. There are the odd few who won't mix with either sows or boars but that is probably the same as within the human race.
I have recently had my boar called Shaun neutered, who is 2 years old. He fought with his brother, so I had to separate them. His brother, Stuart, was subsequently neutered and now lives very happily with Sparrow, a sow. Shaun has been living on his own since and he is lonely. I didn't want to put him through an operation, because of the pain and the expense, but reckoned that his quality of life would be much better if he had a partner, or two, to bond with and live together forever.
He is a lonely boar in waiting until after his 6 week post operation recommended time so that he can't make a sow pregnant. Since his operation I have adopted a blind little sow called Princess and her sister, who I need to grow just a little before introducing them ... gradually .. to Shaun. I hope all works out for them.
Rescue Centres neuter boars to stop any unwanted pregnancies and also heighten the chances of a boar finding a new home as he is able to live with either sows or boars.
Hope this helps with your question regarding neutering.