Advice - Different Religion

So I'm having a pretty rough night to say the least.

My boyfriend and I have been talking about marriage and a really close friend of ours has hinted he intends to propose soon. However, in the past when he's brought up marriage I've asked him to not bring it up unless he's really serious. So long story short, today we talked about marriage. However, he confessed he's scared which honestly broke my heart. When I asked why he was scared he said it was because of iyr different religions. I am a Christian, my beliefs are in keeping the sabbath but I do not celebrate Easter or Christmas or birthdays or any pagan celebration. He on the other hand is a Catholic. He celebrates Easter, Christmas, valentine's day, birthdays etc. So you can probably see where this is heading now. He's scared that our different points of view on religion will be the reason why we end up breaking up when we have kids because he's not willing to change his religion and to be honest I don't want to change mine either nor do I expect him to change it but I do want him to respect it. So my question is, what are your thoughts or if you have any advice on this I will greatly appreciate it.