When you say "Short" do you mean height, endowment or the time period...
If it's height I'd suggest watching the movie "Shallow Hal"...
If it's endowment, it could either be a fetish or a positive past experience, guys with <4 inches rejoice you're in demand...
If it's time spent, well then you might have a problem. I suggest you create a MS Project file as soon as you fall for someone. Start charting your progress and how the relationship develops. Don't compare yourself to your friends (this is where most people go wrong. Some people are much faster than others in this aspect). If you see a proper relationship progressing through all its phases (Conversation, Caring, Courting and Consensual intercourse) then be happy that you're doing it right. If you're skipping any of the above, then try to incorporate it. Hopefully, you should see fruitful relationships develop with this approach...