Magic itself is a practice which isn't bound to a religion. Many wiccans, pagans, satanists, etc practice witchcraft(magic) but not everyone who practices magic is wiccan, pagan, a satanist, etc. Basically, anybody from any religion can practice magic because it's not tied to any religion, and although many religions disapprove of it, it is one's own choice and their choice alone whether or not they want to practice it. For many people, magic is a science because it has been so successful for them, others say it's bullshit and it doesn't work. And part of this, as many things is your belief in it. If you go into something new with a closed mind, especially something that has such mixed beliefs on whether or not it works, then it will be nearly impossible to believe in it, but if you go into it with an open attitude then you are way more likely to learn something instead of making a biased judgment. That's just my thinking on the matter, just tell your boyfriend that anybody from any religion can practice magic.