As salamu ‘alaykum dear sister,
First, and most importantly of all, you need scholarly advise, and I urge to re-submit your question to
our Fatwa Section.
I am sure you are not alone in this dilemma, as it seems to be less uncommon for a Muslim woman to marry a non-Muslim, although in Islam this is not allowed. The reason it is not allowed is because of the reason which you have expressed. It is not always that love should be reciprocated, because in Islam we are not born for ourselves alone, but for the society which we in our participation will inevitably contribute to in one form or another. Because in Islam, man is the breadwinner, the responsibility falls on the wife-mother to nurture the child, a child which is born upon a fitrah.
That inner knowledge bequeathed to us by Allah (SWT), is our natural radar between determining what is right, and what is wrong in the world. We are born in submission to Him (meaning of Islam), it is the ‘aqd (contract) with which we come into this world upon. This may all seem like theory, but here you are sister presenting a problem whether to raise a child as a Muslim (i.e. one who is in submission to their Creator), as a Catholic or even both Muslim and Catholic.
It could be that when you two decided to marry, that you never considered how a child would be raised –
you only considered each other. In Islam, we should be able to move past the mundane actions, and consider the consequences of our actions. Here, a child is involved, and while you as a Muslim mother want to raise your child as a Muslim, your husband wishes the child to be raised in his religion. I ask you, what is a fair resolve for the child, considering that the child will grow out of the home into the wider world where the child will face many challenges, and some of those challenges will be harsh.
Baptizing a child as Catholic will not make her/him Catholic, and neither will calling them a Muslim make them a Muslim, how they are raised and taught to practice will make the child one or other. Even if there is a merger in child rearing practices between Catholicism and Islam, what will the child consider her or himself to be, and how will that child be able to carry forth this merger of religious practice into their lives once they attend school? Yes, there are fundamental things in common between Catholicism and Islam, but how will the child cope with dichotomies like: One God vs. the three in one, i.e. Father-Son-Holy Ghost? Issa/Jesus as God’s son in Catholicism, and as a prophet in Islam? The punishments that is unforgiveable in Catholicism vs. the mercy in Islam? Added to this, you as the mother was raised as a Muslim and as the mother would be the significant role model, assuming that your husband works away from home.
Surely the main influence will be from you. How then will your husband react if he finds that the child is more Muslim in practice than Catholic? These and many other issues you will have to face living in a secular country with a strong Catholic heritage. If the child is a girl, then additional issues are at play, so my sister you do need to have a long heart-to-heart discussion with your husband once you are familiar with what the Muslim scholars have to say on this issue.