need advice for my friend

[ROR]

i am writing on behalf of my friend who is currently eea2 residency holder on the basis of marriage with eu national, now he wants divorce from her wife and both agreed on divorce. But he cant decide which reason should he give for divorce either Adultery, Unreasonable behaviour or 1 year separation. His wife did all of those above things, she cheated my friend now she z with new man, her behaviour is not good towards my friend and they are married for nearly 3 years and 1 months by now but with 1year separation which started from last year (3rd year of marriage).
Now my question are:
Which reason should he use where he could get divorce easily???
And on divorce certificate does it states the reason why this divorce happened?? Anyone with ROR please give your suggestions??

thanks.

[vinny]

Is this a different friend?

Please continue in previous thread.