Is it normal for my boyfriend to be looking at his ex on facebook?

[Eva]

Me and my boyfriend have been together for a year now, im also 8 months pregnant with him. Yea fair do's I shouldn't really of been looking at his private life in the first place but at the same time I would still be deluded into thinking he is in love with me. On Christmas eve I was told that my boyfriend could potentially have a 1 year old daughter. I tried confronting him but he kept saying that there was not a chance in hell that she was his even though when the mother told my boyfriend she was pregnant he turned round and told her that it couldn't be his because he couldn't have children :-S so I decided to do my own research and try find out the dates and so forth. Ended up finding out that he had been asking other girls to go round to his whilst his parents where on holiday I was 1month pregnant at this point too. A few months after that I was sitting in his house and I went through his history (he did used to check on me a lot too Wich is partly the reason I did this thinking he might be hidind something himself Wich I was right) he had been looking up all these girls accounts on bebo. When I asked him why he did this he said he only went on these accounts because he thought they were fake! Yesterday I went on his facebook account just to see if he really had changed his ways and found that he had been looking up the girl who he could have a daughter too and one of the girls he asked to go to his, also his ex girlfriend! And about 20 other girls. What should I do I love him so so much and this is why I think well im not going behind his back because I dont want anyone else so does that mean he does want someone else?