Do I have to inform the girl that I am planning to marry about my infertility problems when it is likely that will be a deal breaker? In that case, what can I do?
You should be very honest, frank and clear with her about such matter if you are medically proven unable to have children. Honesty is more important than a deal of marriage with out informing the girl about an issue which is usually crucial for every girl who accepts marriage with a hope to be a mother in the future. Keeping her in dark is not acceptable at all. If you tell her the truth and she accepts it, then it is good and she can not complain in the future that you cheated her.
Wassalam.