Sex isn't something he's entitled to at any frequency. Full stop. If it's something you both want, and your exhaustion is the only barrier, it might be helpful to have a conversation about how to lower your workload so you have more energy. But any reason is a perfectly valid reason to say no. Of course, there's the nuance of not holding sex over someone's head, but it sounds like that's not what's happening here.
For context, I'm a man in my late 20s married to a therapist for survivors of domestic violence. My wife frequently gets home exhausted and worn down by the horrible stories she hears. Needless to say, our sex life is quite variable. So I figured out other ways to meet my needs (and I would suggest your husband is capable of the same kind of innovation).
I have nothing useful to contribute to the discussion, but I would like to say this conversation feels like Thanksgiving at my in-laws' house.
My (uneducated) guess is that investing and doing business both tend to involve some amount of specialization, geographically as well as by domain and market, so a general purpose online setting might not be the place to go. Maybe classes at a local college or university or a conversation with a domain expert could be more suitable for your goals.