Is it normal that i feel bad about something that happened awhile ago?

Last night, me and my boyfriend were on a call because we dont yet live together. We were normally talking but it ended up getting deeper. We started talking about mental health and serious stuff and he eventually brought up the fact that some time last month, he thought about breaking up with me because he liked his ex at the time. He and his ex are very good friends and he said it was at the time i was worried about him cheating on me with his ex because he sent a screenshot of his messages with her and he called her "love" which is a nickname he usually calls me. I talked to him about it but he promised he didnt like her. This was all last month, but last night he admitted he lied and he didnt want me to be mad, and i wasnt, but later on i did have an entire breakdown. Now I'm worried about that again. I dont know how I can trust my boyfriend, I love him but what he said to me last night was heartbreaking. He kept apologizing and I said it was okay but I really dont feel like it's ok. Is it normal to still feel bad about this even though he liked her a month ago?