It's the same situation as any other individual. To be general it all depends on you if it will be hard or not, and also depends on the situation your in in life.
If you are really picky, which basically means that you have to date another goth, it could be a bit difficult.
Simply because the overall human population is not goth.
But still, I guess that they are enough goths around to date...
On the other hand, if you want to date a non-goth, it could be even more difficult, because not every non-goth would accept your "gothiness"...
To your second point: no, you do not need to have a romantic partner to be a "proper goth" or just a "proper human being".
P.S: "True love" is a vague term. I'd like to think that is exists, but I tend not to believe in it.
maybe... Personally a had a situation when a boy who I liked told me that I am frightening. But I think that someone who couldn't accept my style couldn't be a really good partner for me. But I belive that if someone (even if she/he is a goth or not) searches really hard she/he will find the True Love. :)