Sharing Our Innermost Thoughts

I need relationship advice… so there’s this boy I’ve been dating for about 3 weeks so far. Before we started dating, we we’re best friends and always had something to talk about. I’ll admit these past weeks with him we’re great and all except… lately we haven’t talked at all like 0%. We stopped talking to each other on Sunday morning and we haven’t talked since, we’re still together but even so we haven’t even said Hi to each other. I don’t know if he’s been busy or not because he has a younger brother and I’ve seen his brother go online but not him. I never text first because for me it just feels weird but before the Sunday morning, surprisingly I had to be the one who texted first and say Hey, hru? But he would just say good. Or when I said wyd? He would just say Nm or nothing. And he wouldn’t say how about you? and he would used to say it all the time. As far as I known from him, he’s been in other relationships that were kinds toxic, he would be with a girl for like 3 days and then be with another one the very next day. Which makes me doubt him… we’ve only called each other 3 times even when we were still just best friends we would just text. However, one of my friends is seeing his younger brother and it just so happened that when I went to visit her on Sunday night, she was in a call with his brother talking. I couldn’t help but ask her if I can hear the call as well to see if I could hear my boyfriend in the background, and she said yeah of course you can hear and put the call on speaker. While my friend was talking with his brother, my boyfriend was able to be heard from background noise. Neither his brother or him know that my friend knows me. So when they we’re still talking, his brother said something about “other girlfriend” to my boyfriend. And his response was something of “through discord.” I couldn’t quite hear correctly if his brother actually said “other girlfriend” but I do know it had the word girlfriend and that he said something about “through discord”. Now me and him have matching pfps on discord but I have this feeling he probably sent the same matching pfp to another girl and is matching with them too. Ever since I have him my phone number to talk in WhatsApp, I haven’t seen him gone online on discord at all, unless he’s using invisible mode… which I wouldn’t be surprised because he’s texted me on invisible mode before. But like I said, we haven’t talked since Sunday morning in any app. And on WhatsApp since he has his last seen available, his last seen status was the exact same time we last talked on that morning when we just said Good Morning to each other. I’m seriously lacking my trust in him and I’m not sure if I should say something or break up with him…? I love him, I really do but I’m not sure if he even feels the same way back. Btw we have never fought before either and idk if that’s normal as well? I really need help… because the truth is I don’t know what to do.