Your feelings are not selfish. Don't let your emotions become invalidated by your bipolar disorder. You are still human and not everything you feel has to be stifled or attributed to your mental illness. You are allowed to feel rational feelings.

I know what the depths of bipolar can do to your self-esteem. I get so tired of saying I'm sorry, or feeling ashamed and guilty. Too many times I don't even know what I have to be sorry or guilty about once I think about it.

The feeling that you are experiencing is similar to that of a lot of women, and some men. Holding in this feeling can build resentment and cause harm to your relationship in the long-run. I would really try to express how you feel, and work together to find a way to satisfy this very natural void in your life.

Have you ever considered working from home? Do you have any hobbies, or some you may want to take up? Gardening was extremely therapeutic for me.
(Head with caution. I tend to want to accomplish and start to many hobbies, or become obsessed when I am manic.)

There are many options other than the traditional 9-5 or overnight shifts. I can share some of the jobs I have had that has allowed me to work around my illness as much as possible if you'd like. I have you are able to find a compromise that allows you to achieve you goals as well.