Nothing good will come out of your life if you really do decided to go back to cheat with cheating ex. Just saying.
Don't go with self-fulfilling prophecy, particularly when you're trying to excuse it across this site.
BUT, you're young enough to consider yourself a "Young Adult," married and have a child, so am I guessing right that your child is a baby? The reason I ask is because maybe you're suffering from postpartum depression, not backsliding. There could be a medical reason you're depressed. Go check it out.
(And you have someone to talk to. Your husband. You seem to keep dismissing the guy simply because you think the guy who cheated on you was a "soulmate." God does not screw up who we marry. Fall in love with the guy you married. It's doable with help from God.)