Cheating etc

[Qqstruggle]

Had been with partner on/off for 20+years. Would have never accepted cheating but stayed with / got back with him despite him cheating at least 4 times I know off . Sure there’s more . Had a reputation as a rat . So why did I go there ? Now it’s like I’m stuck .. he has on occasion been aggressive to me & grabbed me by the throat once & poked me in head when holding baby. So much more stuff has gone on ..I stopped living with him some time ago when I had enough. Still in contact cos kids & have on occasions slept together again . I am struggling with PTSD .. feel like I love him still & have this idea things will somehow work out & the loving family life I always dreamed & craved can finally happen. What’s wrong with me why do I even think that when he had treated me this way & I’m here not moved on