upadaisey I posted near start of thread i do believe there are things to sort out for you, and I shared a bit if my story (a bit similar re porn and secrecy but no manipulation accusation of lying)
I would like to add that I think you have done great to wait and not go mental (I did) you seem as if you have been calm and controlled in your handling, although I know you must feel very different inside - you have shown a lot of strength AND not got dragged into sub-issues by others on here.I would like to add:
We had issues with porn (and other stuff) and worked through them (following a seperation) and now are very happy. I know it is not the same situation but being positive I think it is great you have given yourself some space by postponing wedding and going to talk to your parents.
I admire your strength, especially as you have two DC's to care for and pg hormones. I always thought my DH was a good man but couldnt accept aspects of his behaviour, it can help to seperate the two.
I like you am open minded re porn. Having read more on this thread it has reminded me how my DH didnt lie or make excuses he did try to deflect away from issue he was fuming because he got caught and he ran for cover (me thinks) this for us was s ympton of much bigger issues (sorted now after a lot of work) I hope this helps in that you are not alone with having to deal with such crap and there is more than one outcome available, the anxiety to try and sort out and get answers can be overwhelming and all consuming. You cant control him or force him but you can control how you respond - I found this very powerful and still remind me about this now when we argue. HTH ((hugs))
One other thing, Have you thought about what you are going to tell your parents and if they press you for answers as sometimes if you tell the whole truth to nearerst/dearest they may not forgive even if you can so do think about future esp as baby involved.
Hope youve managed a sleep and eaten somthing I wish I could give you a glass of wine too 
Take care x