I came across this blog post on Biblical Gender Roles, the site for all things complementarian Christian. The post is titled "Why a Wife Should Endure Painful Sex with Her Husband" and struck nerves with some female readers. The original poster stated that the post does not advocate for sex right after surgery or childbirth, sexual sadism (not sure if this refers to consensual BDSM activities or not), or that the wife should never bring up an issue of pain. It then goes on with a "Stop reading if you aren't open to new ideas" list, which is usually a red flag that indicates that a provocateur or troll is behind the content.
One woman said that she became "virgin tight" after a C-section. Others said that having sex with a more well-endowed man was painful. Some Bible passages (likely taken out of context) were used to justify enduring painful sex. This post suggests using visual cues to indicate pain and trusting that a husband will pick up on them and seeking treatment from a doctor. All in all, this is sensible advice. However, the sensibility stops at a certain point when it suggests that women who have chronic and untreatable dyspareunia not only endure painful sex but hide indicators of pain as much as possible for the sake of their husbands.
The post went on to say that some women are "china dolls" and cry at the slightest bit of friction and need to "strengthen themselves". Others are said to cry out of manipulativeness. Below is a direct quote:
But from a Christian perspective we must realize that sometimes it could be the woman who is in the wrong for crying throughout the entire sexual experience. If a woman is crying to manipulate her husband because she simply did not want to have sex or to make him feel bad for wanting sex when she did not then the sin lies with her.
This advice is not only bad but dangerous as it condones traumatizing women who likely experience a great deal of shame around difficulty with sex at best and encourages marital rape at worst. Sex is likened to water in this case and a man's affection to a plant, which withers and dies without enough sex. Women who are already struggling in this regard might feel guilty over "depriving" their husbands--and nothing kills one's sex life faster than guilt. In suggesting that women have to endure painful sex whether they like it or not, it affects more than just what goes on in the bedroom. It promotes an imbalance of power, dishonesty, and a lack of communication in the relationship.
If friction or size is an issue, get some lube (like Sliquid) and experiment with positions and movement styles. If you have dyspareunia or vaginismus, go to a gynecologist or a urologist. Get checked out for endometriosis, STDs, PID, uterine fibroids, and ovarian cysts. For those of you who have chronic, untreatable dyspareunia, find ways to have sex that don't involve vaginal penetration and/or use a sex toy. Be sure to get one for your partner as well. (Please stop over at Hey Epiphora. She is a trusted sex toy reviewer and can guide you in the right direction.)
Just as I am against women enduring painful sex for their partner, I am against men enduring painful sex for their partner. Men can experience pain with intercourse for a variety of reasons as well and should speak up about it if they experience such a thing. In this case, (unassisted penetrative) sex is impossible. Moreover, if your partner cries during sex (aside from unintentionally triggered trauma), you shouldn't even be in a relationship.
The funny thing is, both the OP and I agree that sex is important in relationships, but have different boundaries and senses of sex's role in a relationship. While the OP sees it as a right for the husband and an obligation for the wife, I see it as a mutually enjoyed privilege for both (or more) parties to get to know each other in the most intimate way possible. Some people endure painful sex as a means of sacrifice akin to doing manual labor or being wounded during a war, but I personally think that the bedroom is the one place where sacrifices (aside from those that involve consent and basic human decency) should not occur.