Should I work things out with my husband or leave?

My husband and I have been together for 1 year, and married 3 months. We have been through a lot of ups and downs. I got pregnant on very early in the relationship and that complicated things further.

Well we kept going and even with the downs we had, I felt like we were in love and he has known every side of me. The pregnancy was hard for me and he always was by my side.

But I have recently come to find out that the person I once thought isnt the same one. He was secretly talking to his ex this whole time, for almost our entire relationship. He would lie to me looking at me straight in the face and tell me he wasnt. He would go as far as deleting the conversations, numbers and changing even names. He even sent her pictures of our son and him. He told me that he did all of this because since he was going through a hard time and needed someone to talk to ..he ttalked with her. Even though he also had other people (friends &fam)

that he could have talked to. I talked to his ex sister who he had also messaged and asked and she said that he was the one looking for her sister..and she showed me screenshots. Its not inappropiate but it still showed how he was desperate to recieve a reply from her and sending pics of our son.

All his lies have gone so far that even when I asked him to be honest and tell me the truth, he admitted to texting her telling her to please not tell me anything and that he had ruined everything with me and he felt very bad.

Though out this whole time I have asked him if he feels something for her, because how could it be possible for a human being to risk their marriage/family for someone to talk to. And he insists not to be.

I dont know what to believe or think..even if he only was talking and wasnt inappropiate its still wrong because he lied and tried to cover it up. We have a baby together not even a month old. I am completly torn, i habe cried non stop for 2 days. All i wanted to form a family and be together, and now eveything has come down.

Please someone advise. Thank you