I'm a bisexual woman, but can only give you information with regard to my own particular case. I prefer longer term relationships with men, but every so often the urge to be with a woman becomes overwhelming. Such feelings eventually ended my marriage, even though I never acted upon them whilst with my former husband.
A lot of people think the idea of having a bisexual wife/girlfriend is wonderful, but my feelings are frustrating and painful and they most certainly were for my ex-husband.
I envy people who are either gay or straight because, like most people, I want that special one to one relationship, but unlike most people, I doubt it will be attainable for me. Many people view bi-sexuals as merely 'greedy' sexually, but that is obviously a simplistic notion. Like anyone else, I am unable to change my sexuality for the sake of convenience or even to make my love life 'simpler' and less ruddy frustrating.
I sympathise with both you and your partner, but from my own experience, the feelings are unlikely to go away, though her desire to act upon them may diminish, but I doubt it. I apologise if this has been of no help or comfort to you.
Bisexualism is not always the wonderful, bohemian lifestyle the gossip columnists and film makers would have us believe.