I believe it is pretty common for guys to "go off" their partners when they are pregnant, particularly if it's taken a while to get there. It didn't happen with my DF & I though so I don't speak from experience.

You need to remind him that DTD cannot cause a miscarriage (unless you have been specifically told by your doctor not to DTD). Bubs is quite safe and well away from the area that the action will be in.

If you want to get him to stop looking at internet porn tell him that your computer could end up with a virus that could make your computer pretty much inoperable. I do speak from experience with this one (and it doesn't get looked at anymore). It took a computer savvy friend to fix all the damage.

You will probably find things will be different after the baby is born. A lot of women don't feel like any action for quite a while and their partners nag them silly to get it all back to normal again.