Sometimes we can look back on our behaviour or circumstances we've been in and wonder why we accepted it/put up with it/continued with a relationship (in any capacity). I am not suggesting that low self esteem is the sole reason for this, it is more complex than that. Low self esteem does factor in though and it is entirely possible that an individual may not actually realise how low their self esteem is. This may be because in some respects they have high or higher self esteem about certain attributes of themselves.
It is perhaps upon reflection when they realise that people who have a healthy regard for themselves do not accept certain behaviours and they establish boundaries. Therefore, the fact that they didn't put in boundaries puts into question their self esteem.
Growing up in a narcissistic family system often does not foster your self esteem and so there may be confusion around what self esteem actually is and what it feels like. High self esteem may be, in some respects, an alien concept. A privileged standpoint?
The behaviours you continued to confront were likely your norm but potentially so was the internal anguish, confusion and craving breadcrumbs of affection. Where is the space for healthy self esteem when your body thinks you're in survival mode?
If low self esteem or a rollercoaster ride of different states of self esteem is your norm, then it might not be considered low, to you. Were there times when you were very aware of your low self esteem but ALSO times when your self esteem wasn't even conceptualised?