Hi, Anni.
First, I would advise against the “alternate weeks”. Seriously. Catholics must attend MASS, not a Protestant service. Especially now that your children are approaching the time for First Communion–how can you explain to them that they can receive in YOUR church but not your husband’s church? (Because, quite frankly, a Catholic CANNOT receive communion in a Protestant church and a Protestant CANNOT receive communion in a Catholic church). Can you imagine how the child will feel? Since most Protestant churches equate “communion” with “meal and fellowship”, THEY will be hurt when your child refuses, and your CHILD will be hurt.
Since you were both Catholic when you wed, your husband KNOWS the requirements for your children’s catechesis. He “can’t change horses in the middle of the stream”.
Your faith isn’t something for the children to “explore on their own and choose–or NOT choose–later.”
I know it’s hard–my ex-husband was Protestant and while he didn’t go to church himself he made it really hard for me and the children to go, and was very hurtful in his words and deeds. The repercussions were that my children (now ages 22, 21 and 19) have attended NO church since early high school and seriously question their religious faith. This is something I struggle with daily and pray for continuously. In my case, we “stayed together” until the divorce 3 years ago, but that did NOT help the church/ faith situation–in fact, the constant verbal and emotional battles and stresses may have made it worse.
You have a difficult position, as you want to model Catholic wifely love and marriage issues to a spouse who is not only no longer actively Catholic, but now actively Protestant. From his perspective, he has everything to gain and nothing to lose. If you do nothing, he will continue with the “alternate” and your children will be placed in a position where they think they can “pick and choose” faith–and will very likely choose not to have faith at all, or have at least what your husband would consider a “50/50” chance of picking HIS church.
If you attempt to change anything, he can put himself into the position of either the gracious “enabler”–making YOU look rigid and dogmatical, if not downright intolerant!–or he can come right back and start a real religious WAR, depending on how HE perceives your “rebellion”. NOBODY wins in that scenario.
Probably the best bet would be to get yourself a trusted spiritual adviser (talk to your priest and if necessary the head of the diocese itself). Be non confrontational and not aggressive but assertive. Talk over strategy with your adviser (and pray like blazes!), bring out as many points of agreement as you can, be respectful without being so tolerant that you encourage relativism or indifferentism, and above all, see if you can spark his CATHOLIC faith. A lot of times, fallen-away Catholics don’t fall away because they wake up one morning and say, “to hades with papal infallibility”, or “what I am doing in this church, suddenly I understand it’s the whore of babylon”. No, they “miss” something and they think “the catholic church” doesn’t OFFER that something but some OTHER church DOES. It’s not their real faith so much that they fall from–they are looking for “fellowship”, “support”, “answers”. Check out what his denomination believes, talk casually about whether HE believes in some of those things and why, and point out where what he THINKS the Catholic church says or does “wrong” might not actually be wrong at all.
I will pray for you.