Hurt and confused

So,my boyfriend and I have been together for 6 months. Him and I hooked up before we started dating and I got pregnant. About 3 months into the pregnancy I lost the baby. Well we’ve gotten extremely close these last months. We moved in together 2months ago. Well I found out he was talking to his ex for the first 2 months of our relationship. Telling her “I don’t wanna have a baby with this girl. I want a baby with you “ “ I love you not her” “ she’s too crazy” and honestly just extremely hurtful shit. Is this cheating ? He’s very sorry about it. Apparently. I wanna stay with him. How do I talk to him about this? How do I get over this?i lost my baby back in December. My hearts already broken and I can’t take much more.