Rene,
I have read all of the posts - stay strong! Don't want to add to your stress, you really don't need it, but some dreadful thoughts came to mind.
1. Staying in CH. Does your permit say that you are here because of "Schweizer Ehemann"? If so, is there a risk that once you are no longer married, you will be asked to leave the country? There was a dreadful story in the paper at the weekend about a woman who had been married for two years when her husband died in a hang-gliding accident; her 1yo son is allowed to remain in Switzerland but she has to leave! If she had been married 5 years she could stay. Obviously there has been an uproar over this, but it is not an isolated case at all apparently.
2. Working. How is your relationship with your employer? The law forbids them for sacking you while you are pregnant, but afterwards ... If you have no job, I guess you have no permit? Gemeinde's generally don't like social case foreigners, although, as several have pointed out, hubby really has to pay so you actually may not have to rely on social support i you were sacked?
3 Paternity. Baby's born to a marriage are presumed by law to be the husband's baby, but he can dispute it and demand a paternity test (which my friend did successfully and was therefore not forced to pay for the rest of his life for a child which was not his). Therefore while you are married the baby is presumed to be his. Is there a risk that if your divorce goes through before the baby is born this presumption is no longer there? (surely not, but you never know). I don't want you to be in a situation where you have to prove he is the father with a paternity test, so maybe you should at least wait til bub is born before divorcing, so the presumption is the other way. (not a legal opinon, just a cautious person worrying here).
4. Maintenance. I must admit I was not surprised to read he is asking you for maintenance; with lawyers involved it is generally brutal. Perhaps your lawyer would like to suggest that he married you to get you here to support him while he studies, and now that you are pregnant he wants a divorce because you are no longer "viable". Everything I have ever heard is that men pay dearly generally in a divorce (generally meaning when wife is not working) and now there are working women who pay dearly sometimes too, however, where there are children concerned, the one looking after them gets plenty from the other one. So make sure you keep the kid (make sure the court knows he did not want the child).
5 The child. I have heard that it is almost impossible for a man to get custody. It is so rare that I once knew a man who had to fight for years for custody of his kids even when his wife was in a mental institution; the law is very clearly biased toward the mother (the law and society and those implementing the law as well). Don't worry about this, at least this should be OK.
So therefore; while it might be nice to stay at home with baby and get maintenance from him (ie sue him back) you may risk losing your permit, and in any case, it may not be enough as he is studying, and his parent's money won't be considered in the equation.
So you need to work and therefore risk having to pay him maintenance (this is quite a serious possibility if he lived off you til now). Damned if you do, damned if you don't. Yet, I firmly believe you will be given custody, and therefore the maintenance will swing the child's way and therefore your way. Is that what the lawyer is telling you?
You will really struggle to pay for childcare while working. As you pointed out, it is horrendously expensive, and I don't know how people would do it on one income .... perhaps it is subsidized by the Gemeinde in such cases? I sincerely hope your permission to stay here is secure, as I can just imagine the Gemeinde thinking along the lines of "costly auslander woman with kid .... gotta go!". I would seriously wait two years for the divorce to go through. I do not see many advantages for you doing it too soon (not being a lawyer, just a worrier!).
Last but not least, and I really hate to say this, but Switzerland has an extraordinarily high rate of family murders, where the father loses it and tops the wife and himself (it was not a sexist statement, it is the father that does this). I really would take any threats seriously. Like you, he is feeling enormous amount of stress, and some people deal with it with violence. Loss of control of his life may make him want to retake control. Did you change those locks yet?
Lisa