I'm sorry that you've been let go from your teaching position. Keep an eye open on the teacher job listings. Right about now, many schools are looking for people. It's because many teachers quit just after the Christmas break. So don't give up hope ! there are other jobs out there for teachers.
Also, I've read about many people who've been fired from religious schools for similar reasons or infractions of the rules. If the school has a policy, they have to abide by that policy. Most religious schools are private institutions. That means they can let someone go (legally) if that person doesn't abide by their rules.
And well, there are lots of jobs that have "morals" clauses. So, while dating someone may seem perfectly innocent to us, to the school it may have been a violation of their morals clause. Some schools are pretty strict about things like that.
Hang in there ! It stinks to lose a job you really enjoy, but there are other schools out there who will appreciate a good teacher like you.