Not necessarily. There is another way to resolve your difficulties without resorting to the whole divorce process and choosing one of the five reasons for divorce. If divorce was possible without actually being divorced that just might be a good idea.
Traditionally the reasons for divorce are: Adultery, Unreasonable behaviour, Desertion, Two years separation with consent, Five years separation without consent. if in doubt about which to go for stick with the number one choice.
Go for unreasonable behaviour - it's the number one choice
Most wives or husbands who want to be divorced use "unreasonable behaviour" as the reason. It's the easiest; you can make it all up (make it sound credible) and the courts will be only too happy to accept what you say without question. There is no need to offer evidence to substantiate your claims. The court is really not interested in why you want a divorce.
Divorce is not the only way
However, is divorce the only way to resolve a failed marriage? Well no it isn't. Absolutely not. Often the real reasons for divorce are "We just grew apart" or "I just don't love him/her anymore." No adultery or unreasonable behaviour here, just a relationship that has been in slow decline for years, the passion has gone and the physical attraction has dwindled to zero. We live in the same house like a "brother and sister" and we rub along together out of habit. "Divorce is expensive and frankly we can't afford it."
Continuing with the non passionate and non sexual marriage can be a perfectly good resolution to the dead marriage as long as both of you feel the same way about each other (often by now reduced to a benevolent disinterest) and agree to the new set of circumstances and the "rules" that now apply. Having a living space big enough to give each their own personal space is probably the most important precondition to making this arrangement work. You can have a good life after divorce without being divorced.
The big problem needs to be addressed
Problems will occur when one is happy living in the empty shell of the marriage and the other is looking for a way out. You only have to read the profiles of people on the burgeoning number of married dating sites to see what men and women trapped in an empty loveless marriage are looking for. Either it's a bit of real affection, the sound of laughter in their lives and a stroll along a beach at sunset or it's just great sex and lots of it.
Being divorced but not actually legally divorced
Being divorced but not getting divorced is possible but it can only be done by discussing it together amicably and being honest and open about the ground rules. The most important of which is how both of you would cope if the other started a new relationship or just wanted sex with the first person they met on the internet. It's never going to be easy and if it does not work then a good divorce lawyer is probably the only answer.