Catholics are Christians. It’s incorrect to suggest otherwise.
Getting married “by civil only” is not a proper marriage for a Catholic in the view of the Church. Doing so to not upset anyone’s parents sounds like a bad start to a marriage if you have to walk that much on eggshells just to practice your Catholic faith.
I was married for 23 years to a Presbyterian but I got married in the Catholic Church and wouldn’t have married him any other way. His family was fine with that and all came to the wedding and his mother and brother were in the wedding. There was also nothing “hard” about it and he didn’t expect me to attend his church and I didn’t expect him to attend mine, although from time to time he would come along to a Mass.
I edited this last part of my post because I was confused, I thought the OP was the Catholic. Since it’s the husband (who is not the one posting) who’s Catholic, and my statement was more meant for him than for the non-Catholic in the relationship, I’ll withdraw it.