How to give bad feedback to a man you’re seeing?

How do you guys give negative feedback to your man? The guy I’m seeing sometime reply me 12hours late. After telling me he wants to be exclusive and repeatedly reassuring me that he’s not talk to any other gal. Which I’m not 100% fall for, not until he can prove it anyway. Most recently he didn’t reply to my text in almost 2 days. I notice he was active on Instagram. I had to send a follow up text in the pics. The excuse is very unacceptable imo. I really like him and I want to try and build a relationship with him. I understand that not everyone is constantly on their phone. However this texting habit of his is not sitting well with me.

This Wednesday we’re meeting up, I really want to talk to him about without sounding needy. I mentioned about his texting habit before but he didn’t seem to think much of it. This time I want to know how to address it in a mature manner. Please help