I've name changed for this but I feel a bit deja vu because I posted about almost exactly the same thing a copule of years ago.
My sister's DH has been married before and already has teenaged children. Before they got married they had quite a lot of conversations/arguements about her wanting children and him not wanting any more. She (stupidly/naively) 'forgot' to take the pill and got pregnant. This resulted in loads of rows, and eventually he persuaded her to have a termination at 18 weeks. Amongst his arguments were him being too old, it not being fair on his existing children (even though they have a half sister with their mum and they love her to bits), they can't afford it (even though they both have very good jobs and end up with £1000 per month disposable income AFTER all the bills, mortgage, ex wife payments, etc have been paid). But the money is beside the point, it basically boiled down to him not wanting any more children. I posted about this at the time because she has such a horrible time, and went through with the termination because she was scared of bringing up a child on her own. I was the only person she told so I've had to keep that secret since. Part of him convincing her that a termination would be the best idea was him saying that once they were married he might change his mind about having more kids. 
Anyway, they got married, and seemed fine but she phoned me last week and said she's pregnant again - 24 weeks gone! I was excited for her but she burst into tears saying that her DH hates her for becoming pregnant again, he has three times convinced her to book an appointment for another termination, but three times saw how upset she was at the thought of it and they didn't go. But then he booked her another appt at 23 weeks and took her there. She had 50 minutes of counselling, during which time she said she could feel the baby kicking. She has also in the meantime been going to antenatal appointments and had even found out the sex of the baby at the 20 week scan. Her DH hadn't gone with her to any appointments and refused to even look at the scan photo.
Anyway, quite rightly the counsellor said she definitely couldn't go through with a termination so they went home and her DH kept shouting at her saying she's ruined his life, wished he had never met her, etc. Part of me understands how he much feel cheated because he's had his kids, and now he's got his own lifestyle where he can go out all the time, go on lots of holidays, etc - he's also a very anxious person and is always tidying up - I think he may have mild OCD - so the thought of a baby 'messing that up' would probably really stress him out. But its happened, his wife is pregnant, they are both healthy, well off, etc so he needs to deal with it, and how he's treated my sister is shocking I think.
I asked her why she had kept the pregnancy secret for so long - they've known since October and she said she daren't tell anyone because she didn't want to end up with everyone slagging off her DH.
I know she was very stupid and not fair on him to 'forget' her pill twice as she knew he didn't really want a baby (this time she thought as they were married it wouldn't matter - she still should have told him she'd missed a pill). But how he's treated her since has, in my opinion, amounted to emotional abuse/bullying. I don't think they should stay together - they disagree on one of the biggest decisions of your life.
Anyway, I spoke to her this morning and I offered to go with her to tell our parents - she was nervous of telling them of her own because they would wonder why she had kept it secret so long and would get really upset. But she said this morning that her DH has suggested they both tell them together. I think this is so she can't tell them what he's been like. She's also said that he doesn't know that she's told me and she's going to 'tell me' at the weekend and I have to act surprised as though I didn't know. I'm guessing so that he can put on a happy face and pretend he's fine with it. I want our parents to know what she's been going through because I think they might be able to better convince her that her DH is being a bully. But that would be betraying her confidence and should I just stay out of it?
Thanks for reading if you've got through all that!