If you are questioning yourself and whether or not you are being a good supporter to your loved one, perhaps it is because you are making this one crucial mistake: you are comparing yourself to others. Do not compare yourself to others, as it does not give you an accurate picture of yourself as a supporter anyway.
Here's one of the main points. You've heard the expression, "You can't judge a book by its cover," right? Well, even if you look at another bipolar supporter and think that they are a great supporter, you could be very wrong.
You could talk to them for five minutes only to find out that they are struggling just as much as you are. You never can tell just by looking. So you can't compare yourself that way.
A great philosopher once said, "Never compare yourself to others, for always there will be greater and lesser than you." Now, that's just speaking in general, but can be applied to a bipolar supporter situation as well.
When you compare yourself to others, you are making assumptions that are not necessarily true. You have no way of knowing if what you're thinking is the real story or not. You are only judging by appearances.
For example, say you go to your support group meeting, and you see a couple who always seem so cheerful and optimistic, and who always get along. Can you assume that they never fight? Is it fair to think that the survivor never struggles with their bipolar disorder just because you don't see it at meetings? Or to assume that the supporter never gets tired or feels overwhelmed by their loved one's bipolar behavior just because they act happy and outgoing at support group meetings?
You can't compare your own situation to theirs, because you don't know what is really happening when they are not at support group meetings. They may just be putting on a good front. The truth is that everyone struggles with bipolar disorder, and you are no different. It is not easy for any supporter of a loved one with bipolar disorder.
What you have to do is keep your eyes on your own situation, and function the best that you can within it. Try to be the best supporter you can be to your loved one, without comparing yourself to others.
You will know whether you are being a good bipolar supporter by whether your loved one is responding to your efforts to help and support them.