If you’re not prepared to repent of your sins, to return to the Church and practice the Faith, then what is the point in being married “in the Church”?
CCC #1622 ""Inasmuch as it is a sacramental action of sanctification, the liturgical celebration of marriage . . . must be, per se, valid, worthy, and fruitful."123 It is therefore appropriate for the bride and groom to prepare themselves for the celebration of their marriage by receiving the sacrament of penance. "
And as @PetraG said, one promise a Catholic makes during the Sacrament of Matrimony is to raise their children Catholic. There are other issues which is covered in the preparation for this Sacrament, one of which is to be open to new life, accepting however many children God sends.
IMO, I don’t think a priest would marry you under circumstances where the Catholic party is not prepared to live their life as they should - attending Mass, praying daily, receive the other sacraments ie Communion & Confession, raise their children in the Faith etc.
would I have to confess and be sorry about our marital cohabitation prior to us getting “sacramentally married”? (I am a baptized, non-practising Catholic.
In a nutshell - yes.
Being sorry for all sins of fornication which occured prior to Sacramental Marriage means
- you are sorry for offending God in those ways,
- admitting you’ve done the wrong thing and sinned against God who intended these acts to occur within marriage (Sacramental not civil marriage).
- resolve to amend your conduct - which if you remain chaste until the Sacramental marriage, you will have done.
Best advice - speak to a priest about this, he can answer your questions better than we can, and he can help resolve any misunderstanding on your or your wifes’ part and advise you accordingly.
But as I understand it, the Catholic parties would have to return to practicing the Catholic faith. Another point to raise with a priest is the possibility of retroactive validation.
I found this link →
Getting Married in the Catholic Church which coves about 75 FAQ.
it has to be promised that the children resulting from the marriage be brought up Catholic.
Correct. Obviously there are reasons you aren’t listing here - wisely - why you and/or your wife are/would be against raising the children in the Faith. I think it wise to raise these concerns with a priest as he may be able to help to resolve these concerns - especially as you say you were brought up SSPX.
God bless.