Should I be upset?

Samantha
I am 10 was pregnant today and since I found out about the baby my boyfriend has been acting extremely jealous and controlling. He tells me if I'm on my phone around him that "I don't want to hang out with him" if I wait until he isn't around "I'm acting suspicious". He also looks at things that I like on Facebook and instagram and gives me shit about the stuff I like. 
Meanwhile, a few weeks ago, I went through his phone (to make a point) and found that he had been talking with this girl from his hometown that he grew up with. They only talk on Snapchat so I have no idea what they are talking about but they have been talking for two weeks or more every day. I asked him about it, not hiding that I went through his phone, and he said I shouldn't worry that she is married.
I'm not a fan of him talking to her but at the end of the day I'm not his boss. I just think it's a little weird. So he cooled way off on the jealousy for a while but it's flared back up and now he is talking with three women on Snapchat everyday. 
Thoughts?