Sounds like you and ex have built trust strong enough to agree on such a tough decision. Clearly you both love each other, but the nasty addiction is in your way.
As you know, mine also has addictions and I have no idea if he will ever get completely sober. To me, just b/c he is not using drugs or watching porn for several months, he is not sober. He is not doing these things b/c he is forced to be good. I think if he truly DESIRES to quit, and does not want to engage himself in these activities EVEN IF he will never be caught, that is when he is truly over the addictions.
I pray for you and your xH that the day you two can get back together comes soon!!