I would say so, a mainstream Protestant view anyway! It's what Martin Luther taught, and he started the whole Protestant thing! (With nods also to John Calvin and a few others).

And I'd say it's the prevalent view among American Evangelicals, though many don't practice what they preach. My pastor teaches it, and I belong to an Assemblies of God church, a Pentecostal denomination... which are not noted for being liberal.

Now, that does not mean just go sin all you want! But it means you should follow the intent of what Christ taught, and not any "letter of the law" stuff. As a Christ-follower, you'll stumble lots and lots of times. Don't worry, don't feel guilty, just tell God you screwed up and you're sorry, and ask for His help to do better next time. As the bumper sticker says, "Please be patient, God isn't finished with me yet".

So far as what sexual practices are allowed for Christians inside marriage? I can find only one which is forbidden - withholding sex from your partner without good reason (like being sick or something). Otherwise, whatever you and your spouse enjoy.