I used to think it was wise to neuter male dogs not being used for breeding but after reading about the pros and cons in the following article I have my doubts now.
http://www.naiaonline.org/pdfs/LongT...uterInDogs.pdf
If he is neutered you won't have to worry about any unplanned pregnancies but if you neuter him then you increase his risk of developing other health problems. Even if you neuter him he will probably still try to breed. I know it is tough decision. You might ask your vet what he recommends.