Hi ! I know this can be a sensitive topic, but I think an important one as well. I will endeavor to answer this question generally but helpfully. I do feel that when I am flaring badly it is hard to do any intimate activities--honestly, sometimes I just don't feel like it. Even when I'm not flaring, I do experience the type of fatigue that you are talking about. What I will say is that communication has been most important for me. Actually talking about my needs and my partner's needs are vital in making sure we are on the same page. And sometimes I can say things like, "I'm not sure I want to do this right now, but maybe we can just do XYZ" and see where things go.
I know a lot of people with IBD struggle to talk about it with their partners and sometimes partners are not understanding, which is never fun. If it's getting to that point, I do also recommend talking about it with a neutral third party, like a therapist. I know that can seem scary, but it's mostly to help both people communicate like I was saying above!
Hope this helps some. -Eshani (IBD Team Member)