Taking advantage of lying to spouse

Assalamu Alaikum. I am not disclosing the names for the sake of Allah and protection. You can lie to your spouse about the past for betterment of the wedding. This rule is being taken advantage of by my wife. I was a virgin and lead my life in a very pious way. When I got a chance to speak to my wife before the wedding I was very particular about she having  any previous relationships, as I didn’t want this, but she lied. We were doing good after the wedding for a few months . But I accidentally read her WhatsApp and came to know she lead a very filthy life, a life that one couldn’t imagine. I was heart broken. So when I asked why I was lied about in the first place, she confessed in the beginning that she had physical relationships with kafirs. I wanted an immediate divorce but she is pregnant with me. To clear about what to do, I started reading the questions from various Islamic sites, everything says we can lie about our pasts and we have no rights to ask about pasts to other. Is it applicable before the wedding? She understood this and whatever she confessed earlier now became molestation and disinterest, started lying every single thing. whereas one can clearly say everything happened with mutual interest. I feel more worse now with the lack of honesty and loyalty. I couldn’t take a clear stand about saying talaq but ain’t happy with my life. Can we not know the details about the other person before the wedding. In these days I felt it’s better to ask straight. Now the problem is she is taking advantage and lying to me with every single thing. For example, she is doing things which I don’t like then hiding about it,and  if I ask about it, she is confessing that she didn’t do it.. Its very clear that she is hiding and lying  in the name of protecting the wedding. But it’s totally out of control. And I lost total interest. I don’t want to stay but I had to for the baby and family sacrificing my personal life… please share your insights. I don’t wish to stay in the wedding m if anything has happened mutually in her past, because I was clear about what I wanted in the marriage and also read the filth. It’s difficult to move on.! Thanks