divorce in alberta is always "no fault".
I'm guessing his grounds are breakdown of relationship, no physical relationship for 12 months or over...(as you are not in country)
Adultery is damn near impossible to prove, I tried, got nowhere despite physically seeing the proof.
I know this as I divorced my ex wife after catching her in bed with another man...that was a fun day!
In my case it all happened VERY quickly, after the 1yr apart..I did the divorce myself (which was frighteningly easy) and from initial serving to final judgement took I believe just over 4 months, instead of the 3 years in my home country. Total cost 350 dollars canadian (or thereabouts)
The only advice I will give you is this....if one party is totally determined and set on divorce (as I was) and the other party does not want it (as my ex wife) what chance does that marriage have even if (and it's a big if) you are successful in stopping proceedings? Even if you are successful if there is no marital contact it is cheap to refile and re-initiate proceedings from the start again....and at that point there is nothing you can do to stop it happening all over again, one party not wanting to divorce is not enough if that 1yr apart can be proven. It seems to me all you are going to do is put a nice paycheck in an Alberta lawyers pocket, which he will probably demand upfront, but the end result will be the same. If you have a child together then obviously he could be compelled to pay for his child.
I wish I could be more positive, but obtaining a divorce in alberta is frighteningly easy once minimal criteria is met.
In the eyes of the law, trying to be polite, they define apart as not sharing a bed as man and wife. If he has shared your bed in the last year and you can prove this then yes, on those grounds, you can stop things, but only until that 1yr has passed...eg he slept with you in say Jan 2016, he can't file until Jan 2017.
I realise your spouse visa goes up in smoke, but candidly that is probably what he intends, as unless your papers have been approved and he is locked into the spousal sponsorship contract this frees him from it. Is it fair...hell no, but when a marriage of two persons from different countries breaks down this is the easy way of one party sweeping the other under the rug and forgetting about it. (i would not be surprised if he has not already informed CIC of the divorce filing, so your application is on very rocky ground anyways, as one of the main criteria, a genuine spousal relationship, has just gone up in smoke.).
