Umpire overrules judgment call

[JJ]

I'm with Greymule on this one. Your partner had no business joining this fray - it was your judgement call to make or miss, and unless you ask for help he shouldn't be offering it.
We've both been around long enough to know that we should always "consider the source". If he thinks he can do it all, stay out of his way and let him - I'd never work with him again. If he does this to enough partners he'll finish out his storied career working alone, which is what he seems to want to do anyway.
His intentions might have been good enough - he may in fact have seen the hand off the bag - but unless you ask him for help he should have kept it to himself.
The end result was just what could have been predicted - you BOTH ended up looking bad. Hopefully he learned from what he did. I know you did. Hang in there -

JJ