Why is my bf continuously lying to me?

Before anyone comments that I already made a post about this - I’m only making another one because I’m in a situation where I feel hurt and confused and I really need advice right now . I’ll post the original post and then an update on what’s happened after. Here’s the original post - Last year I told my bf that I am in debt $5,000 on my credit card and I didn’t think he would tell anyone but today I saw his phone that he was getting texts from his mom asking about how it’s going with me paying off my credit card and her saying a person has to earn more money than they spend. He doesn’t know I saw the messages but then today when I asked him it he ever mentioned it to his mom he said he never did and he was like “ oh that’s really personal, I wouldn’t do that..” and then he told me he “would never lie to me about anything” . Now I don’t know how to feel because he obviously lied to me about this since his mom knows about my situation. And now I’m wondering if he lies to me about other things too. Update - I asked him about it again yesterday and again said that he would never do that to me. And when I brought up that my ex would always lie to me he agreed with me that it was disrespectful. Last night it was bothering me so much and so I admitted to seeing the texts and he just got really upset with me saying “what the fuck, now I’m not leaving my phone alone with you”. And then I told him I saw the conversation with his mom and he was like “oh really? Okay show me” and when I brought up the messages on his phone to show him (which were all in Portuguese but I had translated so I knew what they were saying) he denied it and said “oh you don’t even speak the language , she was giving me financial advice, I don’t ever remember telling her about your debt” and I just felt so lied to and I don’t even care that he told her it’s the fact that this is the third time he’s lied to me and when I confront him he just got annoyed and tries to cover it up. I was really upset so I was crying and then he was like “ you’re acting as if I cheated on you”. He just wanted to avoid the argument and was like “let’s just watch a movie and distract ourselves” and then he was kissing me and trying to hug me to make me feel better but I still feel so frustrated and disappointed with him. Any advice would be appreciated 😞