Advice needed please!!!

Shakira
My ex and I haven't spoken in a week I'm thinking he went back to his girlfriend he met during our year break up. I just found out yesterday I'm pregnant but don't know how to tell him without him thinking I want to get back with him because that's not the case. We tried before our break up to have a child but never happened. Now we are on a no speaking term I find out I'm 4 weeks pregnant. I've been trying to text him but he has yet to reply back so I'm thinking not tell him at all but then it'll be selfish. How can I tell him without it being a problem?