Good, I really hope not @Tiann92
Quite a few of the people I know lasted 5+ years in their marriage and some had children but in hindsight all have said that it was clear the marriage was actually about the visa first, love second and of course several years down the line when the going gets tough and you have babies, sleepless night, monotony then you need that real glue and proper love and respect to keep you together.
To be honest, whatever the truth is, if he will not even unlock his phone, show you the full convo, tell you exactly who the person is, if they’re in this country or another and just speak to you about it - then he’s not worth it!
I would walk away, as he’s stonewalling you about this, then what will he do in the future?
He’s not exactly reassuring you is he?
As an example if a partner of mine saw similar messages, I’d show them, explain they had nothing to worry about whilst also making sure they weren’t being controlling or jealous for no reason as it’s also important for people to be allowed friendships etc.