Hyperfocus wearing off

Hi all, I'm looking for advice on hyperfocus in a relationship wearing off after about 18 months with an ADHD partner. As our relationship has progressed, my partner has previously said on multiple occasions that they want to move in with me and they want a future with me (marriage, children etc). However, recently my partner has said they now want to attend therapy for guidance and to make sure they are making the right decision about a life with me. I think therapy is a great tool, however I was extremely caught off guard by this comment. I interpret this comment as a change in my partner's mindset, and perhaps they don't necessary want a future with me anymore, or don't know if they want this, even though in the past they have seemed very certain about wanting these things with me. I am wondering if this is related to the ADHD hyperfocus wearing off after about 18 months in our relationship? I am hoping for any advice on working through this stage. Thank you.