I think this is quite nuanced, OP. Is he flexible? Would he happily change plans if it was someone's birthday/play you want to see/social arrangement? Do you spend other nights together in date like situations?
Personally I like to do stuff and so does DH. We both do lots of activities on week night evenings and so does DD. Because we have kids we often do things at different times as a sort of tag team but now she is older/also runs, we often do some things together, which is really nice but I do also like my solo activities.
DH's ex does not do things that involve leaving the house much and is very interested in cleaning. I am not. We do what needs to be done on the house management front and most of it does happen in the hour before visitors arrive when we all get on it as a team. I have never not gone out because I haven't cleaned a bathroom and suspect this will only intensify as I age.
If DH suggested I should go out less to stay in and clean I would refuse. We do plan some things to do together and he will timetable his stuff early doors to fit with family stuff, but we are both committed to nobody missing out.
Is he inflexible? Do you share any interests? Is this new or was he always like that? What is the time you spend together like? I can't decide from your post if he is inflexible and inconsiderate or just training for a triathlon. These things are very different in my mind. Plus if I thought what DH was doing was pointless, I think it would feel different, and it would be very different if it wasn't reciprocated.
Are you considering children? He would have to make huge changes to his routine for that to work for you, I suspect. I would check this out before becoming pregnant. MN is full of posters who thought fatherhood would change this situation instantly and are very resentful when it didn't.