Since you “think you’re done” having children and clearly not open to life, you would have to lie and fool the priest to get your convalidation, but you would still have an invalid marriage. You can’t fool God.
At this point, all you have is a civil marriage. Your Catholic husband has attempted marriage outside the Church and is technically quite free to marry, since he’s not really married now. The hard truth is that as a Catholic, he’s just “shackin’-up”. On the face of it, he’s probably in a state of mortal sin, and shouldn’t be receiving the Holy Eucharist, but like so many, probably is.
You’ve got much to learn about your “marriage”, your “husband”, the Catholic Church and yourself. Happily, everything you discuss and the many concerns you don’t yet know you have, can all be ironed out. It will take time and some serious discernment on the part of both of you. You’ve taken first steps toward a valid marriage.
You don’t have to convert to enjoy a valid, sacramental marriage to a Catholic, but I would encourage you to at least consider it. You just don’t have any idea what you’re missin’.
Well over 20 years ago, I was a lot like you. I wasn’t Catholic and certainly not open to life. But I met this wonderful Catholic girl who, for some unknown reason, took a shine to me, a no-good, wild party-animal and certified bad-boy. I’d managed to avoid any kind of commitment for years and was quite happy to lead the life of a worldly and perpetually single aviator.
Then SHE came along and changed everything. She wouldn’t move in with me, she wouldn’t even get married at the courthouse. Oh no, she made me do everything the hard way. We had to marry in the Church, which meant all kinds of classes, meetings with Father, the whole ball of wax. Now keep in mind, I had no intention of converting to ANYTHING, especially to a Catholic and no one ever said I had to, but I had to at least gain a working knowledge of the Church before Father would marry us. That was the beginning of my discovery of the truth held by the one true Church. I would have never discovered how great and permanent a true, sacramental marriage really is. I owe her my eternal life, because my eternal life in Christ was her gift to me.