I quit: I beg you to notice that the reason religions give NOT to marry out are not usually those of believing the same way they do. Quite often they claim that whoever marries out is exposing him or herself to the bad influence of the outside world. It's not a matter of what you believe; it's more a matter of who you are, or, more correctly, who you are not.
I'm sure you're honest in giving this opinion. That is, you do believe that being similar with your spouse helps the marriage, and that is as far as you would go. I believe that, just for the sake of clarity, we should be aware that not everyone thinks like you do, but many will say they do, in order to hide their true motives for avoiding "bad association".
If you are or were a Jehovah's witness, you know the reasons why worldlies are to be avoided. Here are some:
The Watchtower, September 15, 2009:
“Recently, a workmate who is not a Witness unexpectedly proposed to me,” stated Ana, a single sister in her 30’s. “In a way I felt flattered, but I quickly suppressed that feeling because I want to marry only someone who will draw me closer to Jehovah.”
The Watchtower, January 15, 2010:
3 “Not everyone saying to me, ‘Lord, Lord,’ will enter into the kingdom of the heavens,” said Jesus, “but the one doing the will of my Father who is in the heavens will.” (Matt. 7:21) Yes, it is not the professing of Christianity that pleases Jehovah but the practicing of it. For Christ’s true followers, that involves their whole way of life, including their attitude toward money, secular work, entertainment, worldly customs and celebrations, and marriage and other relationships with fellow humans. False Christians, however, adopt the thinking and ways of the world, which have become increasingly ungodly during these last days.—Ps. 92:7.