Hi Evey,
Welcome to Sober Recovery.
You will find so many here that have been in your shoes.
Many of us live by the three C's:
You didn't Cause this.
You cannot Control it.
You cannot Cure it.
The first thing to do is read all the Sticky posts at the top of the forum.
Then spend some time reading and posting here and you will see that many people are surviving despite having been in your very situation. It helped me so much to know that.
What you can do is get help for you. I have a great deal of compassion for addicts (I have a brother that is in active addiction and another that is in recovery) but I do not like to hear that an addict failed to disclose their addiction within a new relationship. I'm not surprised, but it's upsetting. You had a right to have that information before getting so emotionally involved, and someone truly in recovery would tell you first, not wait until you figured it out.
I can tell you that you will not always feel the way you feel at this moment. I hope that offers some solace, because I can tell you are hurting badly.
Peace and Hugs,
Hanna