You may have sex after infidelity but that is all it will be, sex. It will not be making love as that is a physical expression between two consensual parties, particularly in marriage. I believe that the worse thing that you can do to your spouse is to be unfaithful. This kills the intimacy that was once shared but now is forever lost. A spouse that has love in their heart placed there by God to share will never contemplate or do such a horrible thing.