Both of you should realise that there is a very high risk of you acquiring HIV infection if you both do not take every precaution to prevent HIV transmission. The only options available to you both is either to completely avoid penetrative sex and depend on other forms of sexual gratification such as mutual masturbation, etc. These methods are relatively safe and carry only minimal risk of infection. Your counsellor should be able to help the two of you in this regard. The other method is to use a fresh intact condom from start to finish of every sexual intercourse. Besides the fact that HIV infection is life threatening, please keep in mind that it is important for you to be available well and healthy to look after family concerns including the care and upbringing of children if any.
With regard to the other part of your question. While 100% prevention of HIV infection of a unborn child cannot be guaranteed, if rigorous care is taken almost all HIV transmission can be prevented. The method is to put the mother on anti-HIV treatment as soon as possible and maintain the treatment throughout pregnancy and after. This can be coupled with a caesarean delivery and not breast-feeding the child. Again I must advise you to visit a competent HIV physician and counsellor for detailed help in management. As another option, you could choose to terminate the pregnancy if you and your husband decide that is the way to go.