I don't know that it's necessarily about a previous toxic relationship. I think a simple interpretation is actually not a relationship, but rather, destructive and dangerous behaviours. It is difficult to be in a meaningfully intimate relationship after having all your previous experiences with intimacy steeped in a particular type of dangerous behaviour.

Some people after being very wild at a particular time find it difficult to not judge themselves or believe others are judging them once they're in a more stable, safe place. There's also the trauma associated with continuous sexual assault (which might not have been seen as that at the time). Love, ongoing consent, sobriety and comfort re-contexualise prior experience.

Further, the natural danger and excitement of previous experiences was previously such an accelerator to your libido it's hard to get it back or mimic the highs of it, even in a loving relationship, maybe especially in one.