You should now consult infertility expert and get both partners screened for fertility.
Get the basic investigations and ultrasound done to rule out the cause.
There are lot of factor which affect conception, lifestyle, diet and stress levels etc are also among them.
the first thing you should know is- infertility means unable to concieve even after one year of unprotected regular Sex. If that's the case it may be due to numerous causes, in womens- it might be due to uterine abnormality,hormonal imbalance, fibroid in uterus,sometimes infection like T.B would have scarred fallopian tube which might be a cause,certain medications, obesity etc. In men- decreased sperm count, chronic alcoholism,smoking,obesity,premature ejaculation,medications, testicular infection or trauma etc.so get this things checked. You should know that there are 20-25% cases where the cause is unknown for infertility.As I already mentioned if you are not concieving for more than one year, you can try invitro fertilisation(IVF) technique which has a good sucess rate.kindly consult a obstetrician regarding this.