When you've date someone and truly wanted a future with them, it can affect you very deeply when trying to move on. I haven't dated many in my life, but I feel at times that I will not be able to move forward due to being so use to certain things in my previous relationship; eventually I will have to, but as for now it is not easy.
What I feel will be hard for me is the insecurities that I dealt with from my other half: Will I make them fully happy so that there will be no nagging or complaints? Will they listen when I have certain things that bother me outside of the relationship, such as stress from work? Will we ever have an understanding? People can't read minds, and not all were raised the same way, so your view of love may be different than your other half. What bothers you should be expressed in a tactful way instead of in a bitter way. Everything doesn't evolve around you! You have to think to yourself; this is the person that I will be spending the rest of my life with or want to; do I really want to make them miserable? Nobody wants to marry someone and be miserable.
All relationships are capable of making it, but many make them about themselves and forget about their other half. Your insecurities should be kept to yourself; the truth will come out at some point. Don't let your insecurities be your downfall.