Girls, Whats the reason for my babymothers behavior?

Me and my ex after 7yrs in a relationship had our first child may 2020, but we broke up a couple months after, but around October she moved on to another relationship, well I'll say around my daughter's first birthday I got a random message from a lady which I figured was a fake profile created by my ex even though she denied it, me and her had not had contact since November last year, and she told me she was in a happy relationship, well fast forward to may she text me from this profile saying that she missed me, that she was pregnant and the baby was due in Sept of 2021, and I reminded her several times she needs to work it out with this guy because it would be wrong for her to do his child what's she's doing to minds,. Obviously she didn't like being told that, she said how he's a POS, which I don't believe, and I told her that the only reason she's talking to me now and sending pics of my daughter was because he's gone, and when I told her that she blocked me. But when we first broke up and I felt like I didn't wanna try to fix it and since she was putting up roadblocks for me to see my daughter I just blocked her, but she told me that I'm so childish and immature and that I will never change, I just wanna see my daughter and even though I had no contact with my daughter couldn't even get a picture, when I birthday came around I still sent gifts, my ex obviously still loves this guy's and hates that I called her out on it, why can't she just let me be in my daughters life
Girls, Whats the reason for my babymothers behavior?
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