Hajj on a lady breastfeeding her baby

Subject: Hajj on a lady breastfeeding her baby
A woman possesses an amount which may suffice to go Hajj for herself and her husband. However, she is breast feeding her baby. Can she delay performing Hajj due to this reason? Her husband is not interested in performing Hajj this year for some reason because Hajj is not obligatory on her husband yet. Would the husband be sinful if he doesn’t agree to go Hajj this year? Your guidance is appreciated regarding the matter.