I'm so confused I don't want to hurt my current partner and child but what if there's someone out there better for either of us.
If you feel this way, if you're this tempted by someone you barely know then do your partner a favour and leave.
You're agonising over someone you do not know. You're considering losing your partner, risking what you have to explore something with this stranger.
That means you are not in a happy relationship.
It's ok to end a relationship, it happens. But more often than not people explore something with someone who has turned their head while still in their relationship so they don't risk losing both people. It's pathetic and cowardly. And so cliche.
If you're this tempted then leave. Then you can see if there's someone better out there.
It sounds like you're with your partner because you're not sure there's someone "better" out there or not. How hurtful and cruel to stay in that case.
Again, if you feel the way you say in your post then give her a chance to meet someone who will appreciate her and treat her well - leave her.
Don't try to have your cake and eat it too. Gross.