advice...

So me and my ex broke up about 3 years ago, he moved on is expecting a baby girl and is recently engaged. My feelings for him are completely gone but he was the ex that I feel that ruined it for everyone else that tried to come into my life. Every time I want to get close to someone I always end up thinking about the shit I been through with him so I back off... anyways I recently started talking to someone who I use to talk to in the past I love him and he loves me, we don't go out yet but it's whatever I'm not rushing it but he has two kids two baby momma's which is fine cause he has full custody of his daughter but I just wanted to know is it wrong for me to sometimes look up the second baby momma who he just got out of a relationship about 6 months ago on fb cause I sometimes feel really insecure about myself and just sometimes feel like she just gonna pop up in the picture again even though he says he is over her