Honestly IMO it all comes down to trust. My boyfriend actually sucks at replying and this has always been the case. He’s just not good at it ? He never knows what to say unless we’re on a call. He’s always been a Lil awkward tbh. But if since this is recent I would say try to talk to him, and since that already failed maybe he’s going through something? Sometimes people have their days, weeks, sometimes even months. Just bc he’s not texting u the same doesn’t mean that he doesn’t love you anymore. If he reassures you that he’s still interested then I think all you can do is stand by him. Then again, since this is a long distance relationship try letting him see ur pov and how you think daily commits important. I have two friends that are in a relationship. At first they would text all day every day, now they text every day but not as much, just a couple times a day. I asked my friend why that was and she said it’s because she doesn’t think it’s necessary to talk every second of everyday, as long as they know the other is okay, especially because sometimes they are super busy. However, they do see each other most days, so I see how the situation is different here. I think most importantly, be sure that he knows how you feel.