Huge hugs dynamicbuttler,
You had a bad experience and you got back on the horse to give it another ride. It sounds like you've got some triggers to work through and how you choose to do that is up to you.
What works for us in fantasy, doesn't always work for us in real life. There's a big difference between a set of handcuffs that are unyielding and wearing velcro bonds that can easily be removed.
If you want to try bondage again, take baby steps to help you through those triggers.
Often after a heavy, exciting or emotional scene, a sub may cry as part of their release mechanisms. It's cool.
It sounds to me like you might have experienced a bit of "sub drop" and needed some tender after care. More so that you realized.
"Is there any way to train yourself..."?
The right domme/girlfriend for you is going to understand those moments. You cry, you recover and she works with you to discover what you need after.
When you reach new heights, and are in a safe space, you may continue to cry or not. It all depends on what the two of you are up to and what it triggers inside. If you look at the tears as a friend, a positive release of emotions, then the experience takes on a whole new meaning.
Ruby