Yes it is, and yes it can. Just one example of several I know of--my uncle came from a Christian family, his deceased wife was Catholic, and his son from that union was also baptized and raised Catholic. My uncle remarried a Jewish woman a couple years after his first wife's death, who also had a daughter from a previous marriage who was Jewish.
They had a hard time finding a priest or rabbi who would marry them! They looked high and low--I think it was some non-denominational fellow. Furthermore, my uncle, although raised a Christian, spiritually considers himself more of a Taoist.
The keys are a mutual respect, acceptance, tolerance, willingness to allow each other to believe whatever they want without judgment, and a willingness to maybe not take their religion so seriously that it affects their marriage. The new family lived happily and successfully together, and decades later (they married in 1985), the kids are grown up with kids of their own--and they too, are married to people of different religious traditions!
I asked my uncle, how do they decide what religion to honor, like for weddings, funerals, holidays, and so on--he said: "all of the above". They celebrate all the holidays, Jewish AND Christian. They negotiate and compromise on anything else, and are not too worked up over the result.
My wife and I are also of different religious backgrounds. When we met, I considered myself "agnostic" and my wife was Mormon. I was fully prepared to accept her with her religion, and even her kids (her Mormon husband abandoned her with four children--one with Leukemia). I accepted her, but her Mormon foster family and her church were unwilling to accept me, and they excommunicated her when I came into her life. We both said "good riddance" and 20 years later, I'm now more of an atheist, and she's someone who you might describe as "believing in a higher power of some sort" or "spiritual but not religious".
Hope this helps.