Wow, so many people focusing on the marriage instead of the mistress.
But my mistress was much much more.... Sucks to give her up... not fair to her.... and I'm realistic
but lately she has hinted at being alone... not wanting to be alone.... Never putting pressure on me but you can tell she is not happy about things...
Instead of perceiving what your mistress is thinking and feeling, perhaps you should actually have a discussion with her. She might be wanting to be alone, but maybe there's something else going on. Usually your gut instinct is correct, but initiating a conversation with her might be the best approach. It sounds like there might be a chance that she doesn't want to end the relationship.
It's good that you realize that the relationship with the mistress is the temporary one, and good job on keeping it up for five years. Most relationships with a mistress come to an end. The good news is there are more women out there who will take the roll of a mistress. My only suggestion for the next one is to find a woman who's not happy in her relationship either. You should try finding someone with an even playing field so if either of you get caught, you both have something to lose. My only hope is that your current mistress has enough respect for you to avoid ratting you out to your wife.
But again... before you end the relationship, perhaps you should talk to her about it. You'll be grieving if the relationship ends. Try to have a plan for how you're going to deal with the loss of your mistress, especially since you're still with your wife. She might notice that something's going on with you. Make a plan of what you're going to tell your wife so you can have some time to grieve.