Catholic weighing in.

Cut him loose so he can find a good Catholic wife. Stop being a bit of dead wood, holding this poor bloke back from a better future with someone who is 100% in. The fact that you have been going out forever, engaged forever and still not married? Just. Let. Him. Go.

Reasoning: if you limp along together, with you deepening your Jewish faith, it's going to be at best awkward and at worst offensive that you won't celebrate Christian holidays, even in a 'secular' sense. You'll get more resentful and my guess is that over time, he will too. There'll be other niggles, too - food rules and what not. General social issues. It's going to weaken your (potential) children's faith if one parent strongly believes one thing and another is like meh. A city divided. Further, if he - like you - suddenly decides to delve into his Catholic faith and deepen it, I foresee issues ahead around child-rearing. He will (or should) want his children baptised, for example, or he will want them to do the sacramental program etc. When I married, in the back of my mind, 'Catholic' was on my checklist. Even though at the time I wasn't actively practicing, I wanted to marry in a Church, have any children baptised and so on and so forth. That was my thinking, a very lukewarm Catholic at the time. I'm so glad I did (marry a Catholic, albeit a lapsed one) because we have no friction over these things. There is a renewed effort between Jewish and Catholic leaders to try to heal old wounds. But still, it would be a tough gig for two practicing parents - one Catholic, one Jewish - to agree on some important things.