Am I paranoid

Me and my partner have been in a relationship for some years now. And I'm pregnant with our first child and we are suppose to be getting married soon. But last year and this year I found out that my partner has been on these dating sites and other different sites like "tagged and badoo" etc. When I found out that he was on there I confronted him about it. And he lied to me saying his not on there etc. Will we argue about etc, and then this year after asking some many times he confronted to me that his on there. He would chat up all these different girls and flirt with them, still talk to his exs. So anyway as usual I would forgive him, we had a big discussion and he said he will come off these sites etc. Because he doesn't want to loose me or his child. But recently I've checked to see if his still on these sites and he still is. And he has girls names save under different names in his phone book. I don't understand if your not messing about you wouldn't be on these sites or save a women's names as a man. Plus he as Instagram, (I may be a bit parraniod on this part I don't know) he has all these girls on Instagram, and he keeps on adding random girls on Instagram. He kept on liking girls pictures with hardly any clothes on, so I asked him what do you like about her for you to like the picture. Because  it cannot be her smile if she's half naked.