Deborah, I don't know why we are still single, but *perhaps* it could be because of sin in the world. I don't mean that to sound simplistic, instead, I think there are a lot of factors that get in the way of us meeting the right person or being fully prepared ourselves for marriage.
For myself, I look at my upbringing and I was
very sheltered. Being raised that way certainly did not prepare me for a relationship, and it took years for me to mature into an independent person. So while I am not pointing fingers at my parents, I do think, objectively, that their choices to
discourage me from becoming independent affected me significantly. In my 20s, when other people were dating and marrying, I was still struggling to become emotionally and socially mature. (Still working on the social part ... LOL.

)
And also it seems like people (both men and women) have a warped sense of how 'perfect' the other person should be, and I think media images and other social influences have something to do with that -- with creating unrealistic expectations. To me that's caused by sin (how we love to worship celebrities, etc., and then people end up feeling they don't measure up...)
I don't know how many relationships you guys have had, but some of the ones I've had *could've* worked, but one or both of us had issues that got in the way.
Again, not trying to blame anyone. After all, the battle we fight as Christians is against the devil, not one another. But just making an observation. We live in a fallen world. Some people value their jobs over their relationships for example. It's no wonder we have a hard time meeting people and dating.