Mulven, no we were not co-ordinated betting in order for bets to cancel each other out. I'm not quite sure what you mean by arbing. That I think would only occur with laying off a back bet with an equivalent lay bet. The bookies hate it because effectively they have offered odds that are too generous. Although that might be a reason for closing an account I don't quite see how it could ever justify confiscating someone's winnings. Because they would in effect be admitting that they fix the odds in such a way that the bookies always win, and on the rare occasion when they don't, and someone actually makes a profit, well then they just steal their money. Hardly a fair playing field.
I wasn't suggesting you co-ordinated to bet on both sides of an event outcome, I was just saying that it could have happened accidentally. If you were intentionally doing that you would have used an exchange!
Arbing doesn't necessarily involve a lay bet to lock in profit as you can advantage play them too.
Isn't the whole point of a bookmaker's business to "fix" the odds so they always win via the vigorish/overround (similar but slightly different things).
For most players if they are winning players they'll get stake limited, promotion restricted or accounts closed but not winning confiscated.
If you were matched betting, arbing or constantly taking value/making profitable bets then they might have used the fact you lived together to push the narrative of fraud, allowing them to confiscate, something that wouldn't be possible for a standalone gambler with no conflicts.
Are you a winning player at most bookmakers you play at? It definitely sounds like you are familiar with laying bets and have intimated you are a winning bettor.
I would definitely suggest that you and your wife shouldn't have accounts at the same bookmakers, even if they have terms allowing it. That term is, as you suggested, only really honoured for losing players. If you are both constantly taking value from the bookmaker they can easily make the claim that it is fraud and that one of you is playing on both accounts. Under the circumstances this would be hard to disprove. As mentioned before, this isn't a course of action possible against a solo player so they would grit their teeth, pay and ban the player worst case.