In choosing a life partner, is religion an important factor to be consider?

I don't think religion really matters but it may in your case because your mother feels so strong about it. My husband and I are different religions and it hasn't brought about any major issues but it has brought about some little fights at times with my mother in law. It's very rare but it has happened when she doesn't get her way. I think everyone really needs to be on the same page with this decision. If you don't care and he doesn't care you need to sit your mom down and explain it. She may not like it but I think if you really love someone it shouldn't matter.

Yes, religious position or lack of it is one of the things that must be examined. Imagine me, an atheist loving a deep catholic girl, would never work. And if we had kids, would they be free to choose (my opinion) or she would impose her religious views. Sad as it is, religion sometimes can destroy a relationship. Side note : I am not telling that religion is sad, instead I am saying that religious differences are sad and can destroy a relationship.