Are you certain that the husband is dead? In the screenshot you posted, he didn't look like a ghost. Is there a different Special Merchant now? If he's still living, your Sim just needs to get face to face with him, pick a fight, and break up. The Science Facility thing isn't a bad idea, but I don't know how you could get his remains. Try going to the cemetary there and clicking on the masoleum to see if "Manage the Dead" comes up as an option. Also, when you bring a spouse back from the dead, the relationship is "fiance" for some odd reason. She could still break up with the ghost, I guess, but he won't be her husband. Do you have control of the new Sim she's in love with? If so, I'm curious what her marital status shows when you click on her from his relationships tab. Does he show her as being married?
On the pregnancy thing, your Sim won't show her pregnancy until she gets back home. I've had a couple of Sims who had babies with foreigners and neither showed the pregnancy even though I got the lullabye chimes.