I believe they are all important issues, as they have eternal consequences.

Christ already demonstrated the conditions that constitute adultery. I've provided a number of quotes that spell this out and are most clear.

Of course this is one important issue amongst many, but why not address this too whilst we're at it? HOw can one claim that having more than one wife/husband is not adultery? - even divorce is not always recognised by Christ (depending on the reason) - so if they divorce when Christ considers them still married, and they go onto marry another, it is said they are committing adultery.

It is clear therefore that marrying another, whilst still married is adultery. How can polygamy be an exception? Christ has set the conditions, but are we obedient to them? Easier said than done for most of us!

The grounds for marrying another, are strict and appear to be limited to (if I'm reading correctly) - death of the spouse (till death do we part), or if the spouse has been unfaithful. The only other of course, I gather, is if the marriage was not valid in the first place - or consumated.