<human>: Condense the text into a few key points

I've been dating this girl for about a year, and now circumstances have finally evolved to allow us to move in with each other into an apartment. This is a huge move for both of us, since neither of us have lived with an SO before.

However, I have an embarrassing medical issue that may cause some problems between us. Basically, I have irritable bowel syndrome that causes me alternating bouts of constipation and diarrhea. When I'm constipated I tend to have really bad flatulence (not just in terms of quantity but also in terms of exceptionally foul stench). When the shit finally hits the fan, so to speak, I end up take 45-minute long dumps that are both noisy and leave a rather epic atmospheric contamination in the bathroom for a while afterwards. 

We've already looked at an apartment we want to move into. It's really nice, but the bedroom is right next to the bathroom, so my shits will DEFINITELY be audible from our bed. They may be smellable as well, depending on the level of severity. In the past year we've been dating I've managed to hide this from her, but when we move in it will becomes quite apparent rather quickly. I'm wondering if there is a way I can bring this up to her without grossing her out. Or, should I just not mention it and act like noting is wrong? She's really nice and understanding, and I don't think it's likely she'll just walk out because of my nasty BMs, but I feel I should breach the subject with her, and I want to know if anyone has any advice on the most tactful way to do it.
<bot>: Moving in with my girlfriend soon, have IBS that gives me bad flatulence and nasty shits, wondering how I should bring this up with her before we move in together.