The short answer is yes, he is a virgin. Basically, Kylo Ren never had personal time to explore his sexual desires. He is either too busy running the First Order or training his Jedi skills. He never had a close friend that he could trust.
He was sent to Luke’s Jedi academy when he was 10 years old. This is before is puberty so he probably did not have any sexual urges before. In Acadamy, he got little to no privacy. His mind was occupied in mastering the force. At the age of 15, he and Knights of Ren attacked and killed the rest of the students in defiance for Luke’s attempt to kill him. After this, Kylo had to balance time training with Snoke, lead the Knights of Ren and leading missions in First Order. He spent a lot of time getting people to fear and respect him.
For somebody who never had the experience, it was something that he is not interested in. Even if he wanted to and have time for personal activities, any suitable female companion would be a subordinate to him. I doubt he would want to show emotions or have feelings with anyone that he suppose to give orders. If he did, he would look weak in the eyes of the First Order. I doubt Snoke would want him to engage in any carnal pleasure that might distract him from the true purpose. Snoke would have gone to great lengths to prevent this.
In Star Wars: Episode VII – The Force Awakens, he is shown to be uncomfortable being close to people both physically and emotionally. He tends to cover himself from head to toe in all black clothes. Sometimes he does not reveal any skin at all. He mainly covers his face because of his insecurities and emotional weaknesses. Kylo/Ben looks somewhat like his parents. He does not want to be reminded of them. Therefore, I doubt he would want to show his inner weaknesses to anybody. The only time he ever showed an emotional connection was to Ray when he asks her to give up everything and come with him in Star Wars: Episode VIII – The Last Jedi. We might see more of this chemistry develop in Star Wars: The Rise of Skywalker.