Things that happened can't be changed. Why bother going back in time to relieve those memories and dwell on them?
By dwelling on something negative or on something that didn't turn out the way it was supposed to, you're letting your negative emotions control and consume you.
By going back in time and visit the past your shocking your body.
Kinda like when you jump in a pool of water even though its been hot outside for a while but the water has't quite warmed up yet. It takes you aback for a second until you finally stay in long enough for your body to acclimate itself to the water.
That's what your doing to yourself when you bring something up from the past, it's a shock in which you have to sit with those doubtful emotions for 10- 15 minutes as long as a day or two in order to be okay with yourself after visiting the past. You don't need to do that.
Remind yourself that you are stronger now than what you were in the past.
Whatever happened, there is no such thing as a coincidence, everything happens the way it should... and with perfect timing I might add. You loose people or things in order for the Universe to teach you something or better you in some way.
Sometimes you have to let go of things for better new things to come along.
"You can't have your cake and eat it too."
You don't need the extra baggage of holding onto your past, all you need is an empty lounge case for all the memories and experiences you will now be able to experience in your present and future.