SO & porn :(

I'm 10 weeks pregnant and my SO has been masturbating and watching porn a lot lately. He knows I hate when he watches porn only because I'm super insecure and I don't like the fact of him looking at other women naked, having sex. (Please don't give me a speech on being controlling or whatever. I can't help the way I am). Well it's gotten so bad that he goes into the bathroom to "take a shower" instead he'll turn on the water and just masterbate then he'll get in, 20 minutes later. I don't care if he masturbates, it's totally natural but I don't get why he isn't respecting my thoughts on it and why he's trying to hide it and lie. We've been together over 2 years & we have sex frequently. I don't get it. I hate it. Now he has a "keep safe" in my phone and I'm not sure what for, considering he doesn't have pictures of me like that. I need advice on how to try and handle this situation.