my husband takes salazopyrin. we want to get preagnat. He is on them years and a high dosage. will this effect our chances

Salazopyrin is know to cause sperm count issues in men. 

The first thing I would do would be to request that a sperm analysis be done so you can see exactly where he is as far as his fertility is concerned.  

There are treatments out there that can improve sperm count- both medical and herbal so it worth asking your physican about.