How would you handle this

So I made a poll last night but I have more to add, my boyfriend sent a text two nights ago at 10pm to a unsaved number saying I’m on my way. The number didn’t respond or anything, when I asked him about it, he got angry and just started saying sarcastically that he’s just out fucking bitches. He texted the number in front of me and said who’s this and even called it but the call said the number was incorrect.. he denies ever even sending the text.. but his roommate says he met up with a guy last night for his weed, but then why would he deny that? A text doesn’t just randomly pop up as being sent from you out of nowhere?? What would you do? I want to just drop it but it’s sitting so uneasy.. we have another baby on the way right now too.

Edit he had me text his sister for him from his phone that’s why I was on his phone, but he also shares his location with me on the life 360 app I never check it but he showed me all the places he went last night and it only shows a quick trip to the store at a way earlier time.. nowhere at 10 pm and he was still texting me, so I really want to believe him, but a text doesn’t just randomly pop up on your phone as being the sender???