I am glad to be married. My husband and I compliment each other in so many ways. We have fun, share common interests, and also have our own personal interests. That means, if I go to the ballet, I go without him. If he goes to the car parts yard, he goes without me. So sometimes, we are alone in our activities, but we do find time to spend with each other. I used to be very lonely, especially when he went away for work, but now I am finding his retirement to be a bit of a challenge without having enough "space." This is something we are working on, and he has been very good about it so far.
My personal opinion though, is that we should always put our ultimate companionship, love, and desire in God. My security comes from God, but I do trust and love my husband. Remember that people fail us, make mistakes and they also can die. Marriage is special, if you do find the "right" person. Meaning someone that you love and are loved in return, serves God, and you can share a life with.
I can't comment on whether some people are not cut out for it or not, since I have been married so long, I barely remember not being married. (33 years!) I think most people are probably "cut out" for marriage, since the majority of people do marry and that was God's plan in the Garden.
But one should marry I think they should seek God's will as to whether this is God's plan for you life. A single person, in my opinion, can do a lot more for God than a married person, and I know Paul says something to that effect. But if a couple wants to serve God together, what a wonderful blessing. Two of my seminary profs have been missionaries together, and I know a few other couples who served together on the mission field. But we can serve God at home, and raising a family, so everyone has that opportunity in Christ.
I don't know if that helps much. Just to tell you, it works for me!