Low self esteem due to single parenthood

I’ve developed low self esteem due to being a single parent. It’s my own fault because I compare myself to my ex’s other bm and how she’s done worse to him and he’s stayed. They both cheated on each other and still stayed together. However my ex broke up with me just because I was “spying” on him and he called me crazy. When in reality he was looking for any excuse to leave because he thought i was ugly and unattractive and he probably never cared for me at all despite carrying his child.

So i just feel sad for being a single mom because my ex’s other bm doesn’t have to be one and she gets the support of his family. They moved out to be closer to his family while I stayed in the state im from. So now he’s wanting to see her weekly despite the plane rides that are going to be had.

And then his bm threatened myself, my mom and my own daughters life! She’s batshit crazy and fights people but I was the problem. She literally beat him up and physically hurt him. So I’m just not getting why he went back when I would’ve never done anything like that.

I know I shouldn’t pay attention to it but idk I feel like I got unlucky and made a mistake. ;( I don’t regret my daughter but I wish I would’ve had her with someone who loved me and cared for me and wanted to stick by my side. 😭