Any go through peroid of inappropriate
You are not responsible for anyone else's behaviour but your own.
If these women are making themselves available for you, then the impact on their relationship is not your fault.
I would however look at the reasons for what is going on.
Why are you not interested in moving on after so long?
Why are you doing the same thing your ex is doing?
It may be an idea to speak with someone about what is going on so you can work through this.
I would also stay away from both of those women. They will not leave. They are unhappy in their marriages but there is something that is holding them there. That is unhealthy for you.