Marg66,
Celibacy is a word designed to describe the state of a single person who live in continence.
Many people abuse this term and employ it to design a person who simply live in total continence independtly of his marital status.
Your friend is a divorced man, and who live in continence.
(And in a relationship with another woman and now consider a civil marriage while keeping continence).
I know that sadly and injustly many people have been left by their spouse and their best efforts to bring them back where unsuccessful. It seems that if they remarry they will not harm their ex-spouse.
Yet we believe that marriage is for life. A valid Catholic marriage can be dissolved only by death. If the husband and wife separate, maybe with a civil divorce, they should remain faithfull each other. Doing otherwise will be adultery and maybe a bad exemple for others (that’s why I speak of scandal).
I understand you have no wrong intentions and try to do what is pleasing God. It’s valuable that you are both willing to not iundulge in the physical part in respect of your husband’s first marriage (that’s the goal of this Church’s rules).
We know that there is a possible pastoral path for people who are divorced and fall by a new civil marriage and married life. That keeping continence may permit them, under their pastor’s direction to go to on the sacraments again.
Your situation is reverse, wanting marriage without consumption, in order to conform the rules. I am sure that you are not alone, but it is more uncommon to put the things like that. I have no idea what the Church’s answer would be. That’s why I suggest that you speak to your pastor. It’s better to anticipate the things, to have a view on your husband’s first marriage, and what the possible consequences of what you planned may have for your catholic’s life and your soul.
No priest can forbid you to do it, but for things related to divorce and remariage, it is an excepted step to speak of your priest first
I am not naive and know that in many situations people will make their own choice without telling any clergy and will not modify their habits.