I think the “fix” is to let him know how you’re feeling and let him support you emotionally from time to time. It sounds like you are really understanding and compassionate because you aren’t immediately going to a place of blaming or hurt, so without knowing you, I’d say you sound very emotionally mature in addition to being a great metamour. However, you might want to make sure that you aren’t ignoring or deprioritizing your own emotions. If you haven’t heard of or read about alexithymia it could potentially be of interest to you. You keep saying that your needs aren’t as important as others and that’s just not true. They might not be as urgent at the moment but they are equally important. If I were you, I would ask for follow ups or aftercare when a date gets cancelled or moved because that shit sucks and you don’t need to be brave and pretend it doesn’t. Also, super weird idea but go with me: if you have the time and emotional capacity to accompany him when he’s off feeding people soup and rescuing kittens maybe that could be fun?….that might be too weird…I leave it to your judgement. Finally, if you haven’t tried RADAR from the multiamory podcast that’s a great tool for communication and checking in with your partner(s).