Being there means that you are present physically, or that you provide emotional support in some way. When you are being there for a friend or relative this means that you are helping them through a rough patch or tough time. If you have a plan for your future then you are considered successful when this plan is realized, and being there means that you reach the goals that you have set.
Your soulmate will know exactly how to deal with you, flaws, mood swings and all.
Sometimes, the person who's always been there for everyone else needs someone to be there for them.
Just remember that when nobody was there for you, I was. And when nobody else gave a damn, I did.