Purely sexual relationships usually stay jusf that and don’t develop into anything deeper. Also relationships solely based on sex eventually dwindle and end as sex isn’t enough to maintain deep connection.

I’d say it’s pretty expected that eventually one or both partners would cool off and move on either new partners or on to other important things in life.

If you want relationship outside of bedroom, you should look for that kind of relationship with men who want the same , build friendship and trust etc If you want just sex, it’s fine too but this guy doesn’t appear interested anymore (being busy and wanting to isolate is an old excuse), so it’s better to look for a new guy