there's nothing wrong with you. agree with some guys who say that the sites you're using are primarily for hookups. also agree to some lesser degree that guys around your age are looking to have fun and not get too serious. but with both, there will be exceptions.
i think searching online for relationships is a bit tilted. online personals sites have the user-experience of a catalog. its like we're shopping for something on ebay. and if you think about it, thats just crazy. you can't tick off a bunch of check boxes, press enter, and wind up with a deep and meaningful and long-lasting relationship. human interaction is more complex and nuanced than that.
i think they are useful for socialising, for identifying what and who interests you, for making contact, but the depth and meaning of a relationship is always going to be through getting to know someone. learning to trust them and for them to trust you. and building up some personal intimacy.
some of my gym buddies and sports league friends have crossed over into being personal friends. i think its because through working out or playing sport, we've realised that we have interests, outlooks on life, and other things in common with each other. the rest are just like contacts i'd have at work or school. i also volunteer in the gay community and have met some good friends that way. all of my boyfriends have been made through contact at uni, through sport, or through mutual friends. only one was made through a website (ironically, it was the most meaningful one, but also the most hurtful when we broke up 4 yrs later).