He is indeed being a complete horse's **** on so many levels.
He is in the wrong as a vicar - as Laurel told him, this is not how he would handle the same situation with one of his parishioners.
He is in the wrong as a husband - he should not be railroading his wife into putting up with this menage a trois (albeit not in the actual sexual sense) indefinitely
He is allowing his long held hatred of Vincent (understandable to be fair!) to colour his judgement on all sides
He lied, and yes, in God's House too.
Get a grip Ashley before it's too late.