What do I do when my wife has been lying

We have been married for eight years and I love her very much but have always suspected her of not telling me the truth about her past, she has always lead me to believe that she was a girl of high moral standard (which is important to me) and that she had a very innocent sexual past. I would question her from time to time because her answers would just not feel right, like she was hiding something and over the years she would slip up and the story would change and to cut a long story short she finally confessed that her past was not at all like she has lead me to believe and that she has been in contact with her previous partners , I feel like I dont know this woman and also cant help but feel sick in my stomach, how can you lie and decieve the one you marry like this? At the moment she is pregnant with our second child I am really trying to keep it together but im so angry with her and just dont know how to deal with this.
Can someone please offer me some advice?

I wont say what ur feeling is wrong or ryt cz feelngs cn nvr b jugd. Well, in ur case I thnk u shud cncntrat on wot u hv in prsnt n wot u gnna hv (ur scnd child!), past iz past, its gon. dnt ruin ur prsnt n futur 4 dis, by doin dis ur jst gnna miss a big deal of happines in ur lyf n happines iz nt smthn evry1 gts evrydy!
S far s ur wyf being a liar 4 so long, its nt totly hr fault too. I mean, u urslf wntd hr 2 b s she ws shown u, she js didnt wntd 2 make u unhapy bt thn finly she told u d truth. S u sd u lov hr so mch thn plz frgiv hr n acpt hr dis lst tym. It may b hrd bt d bst u cn do n u shud do. Thnk abt much importnt thngs in ur lyf, lyk ur lov, ur wyf, ur cmn litl baby, ur futur...nthn cn b dn abt d past so frgt it n mov on wid lov
bst of luck :) (y)
bles u, ur famly n ur cmn litl angel :)