Consider this, take out it being NO who is suspected of murdering her kids and replace her with 'Katie'.
Katie gets pregnant at 14 / 15 (could have been consensual, could have not, we don't know), decides to have the baby and gets married. The marriage doesn't last long. Around this time her mother dies, father has already died and Katie is looking after her younger brother. Katie meets a new man and gets married and has another child (there is around 5-6 yrs difference in age btwn the kids, probably not unusual for second relationships). This 2nd husband 16 years later speaks highly of her, despite the relationship not lasting and the pressure of parent’s death, young children, brother etc... Katie still has a close relationship with her brother who speaks highly of how she supported him. Katie has trained as a hairdresser, earned cosmetology accreditation(s) and pulled herself up out of being a presumably, uneducated teenage mother. Her first child, the one she had at 15, is at college. Katie has a large group of loyal friends, seems to be successfully self-employed and generally seen as a really nice person.
I might have some of the timelines and examples wrong, and I haven't dragged out the Katie story to include a 3rd child but I just want to highlight there are many flags of positivity, success and determination on how NO lived her life. Having 3 kids to 3 fathers is not necessarily a reason to judge. Maybe she was a romantic idealist with poor taste in men? We don't know that at 16 she was messed up and severely depressed. Can we please all recognise the fact that she achieved an education / trade, provided a stable / supportive environment to enable her first child to get to college and all the photos and videos of AM and LB show two young girls who look happy, loved and loving.
I'm not at all defending her actions if she did what is presumed, I feel as emotionally devastated as you do about this case, but can we balance how we examine and dissect her life?