Again, you can have sex even if you feel that you have a serious/just reason to avoid pregnancy. It’s called periodic continence or NFP. You just have to be preparing yourself to LOVINGLY accept any child you might have. Oh, and “I don’t want kids” is not a good reason to avoid pregnancy. That is a selfish desire that needs to be worked on through the aid of a good spiritual director, staying close to the sacraments, and lots of prayer.
“I don’t want a child” is not a reason? Maybe life is just not going to allow for a child anymore. So once again, as far as the church is concerned, we either keep cranking out little Catholics or we don’t have sex. THAT is the problem with church teachings. A couple may want to have kids, but cannot afford them or have medical problems, and yes - maybe they do not wish to have one for a while. But according to you and the church, they should say the heck with it, the church says have kids, so here we go. Selfish desire? That is so wrong and presumptive by you and others that say this. It also takes away a lot of the intimacy for some of us. Others have mentioned the same thing that I feel - by using NFP, sex has in many ways just become physical and “oh, well, the calendar says its time, so lets go while we can.” It is not all peaches and cream and the end all be all that it is made out to be.
No, sex is not NECESSARY for a healthy marriage.
Maybe not for you, for others - YES.
Lots of couples have had HEALTHY marriages without sex.
Lots of couples don’t.
BUT I would say that most couples would have sex as a part of a healthy marriage and that marriages without sex can be unhealthy. It depends on the motive for no sex. If a couple is abstaining because they have a serious reason to avoid pregnancy, that is not unhealthy. It’s not the natural order of marriage, but it is not unhealthy. If a couple is abstaining because they have a disordered view of sex, that is unhealthy. Sex is a natural part of marriage and is naturally ordered to the procreation of children.
Again, again again - sex is then only for kids. My motive for sex with my wife is deep, physical intimacy, but that is not always possible following church teachings and since more kids are not feasible. That does not make us selfish. What is more selfish - to keep having kids you cannot afford or be sexually intimate even without intercourse if need be? Who is deciding what is disordered? Obviously, the church which tells us to keep having kids whether we can afford it or not. Saying the natural order of marriage is to have kids says the same thing - sex is for having babies. You cannot say it is not.
IF lack of sexual intimacy is causing a ‘huge toll’ on a marriage, I would venture to say there are deeper problems in that marriage than not having sex. Is abstinence difficult? Yes. Which is why it should only be entered into in the most dire of circumstances when no other moral alternative is available. The Church recognizes this, that is why it spoke on the morality of periodic abstinence, so we would know that there are other options.