Should I allow this? I know sex means different things for men and women but if I shutdown sex in the midst of divorce proceedings then basically it would be counterproductive to changing his mind in this matter.
No, you aren't going to have sex with him, under any circumstances. That isn't going to win him back. Self respect has a far greater chance. Do you want him to stick around only because you had sex with him? NLS, time to start looking at your value in a whole different way, because if you think you are going to hold on to a guy with sex only, you are in for a lifetime of hurt.
Second thing - As Sandi said, this forum is for the spouse who has walked, not the spouse who has been left behind. If you move over to newcomers, you'll see much more traffic and help.