Unexpected

So, my ex and I were together over 3 years and had a miscarraige last year in April on my Brithday while we were still together. We broke up in September 2018 and have still been seeing eachother a few times a week, we want to be with eachother.. but have been working on ourself for the time...

I just found out im pregnant.. clearly with his. Im 5 weeks. I do not want to tell him till i get an ultrasound with a heartbeat.. something more concrete. He wasnt supportive through my miscarriage last year... he had a hard time with the idea of a baby..

Idk how i should tell him when I do.... any advice?