I would suggest you call your internet provider and ask what your monthly usage has been. They may have it on a web site.
I use Verizon for my home internet and traveling. I can't get ANY land line based internet at my home.
I had 5G/month and was constantly going over. What blew my mind is that we do not game or watch movies on it.
I have attributed it to the increased content on most if not all web sites. Go to yahoo, and "mouse over" an ad. Instantly a video pops up. You don't think about that with your unlimited service.
I had to upgrade to 10G/month. It was cheaper than buying the extra gig at $10/gig on overage charges.
If you go over one bit, you get charged for the next gig, whether you use it all or not.
Verizon does not offer an unlimited data package any more.
You mentioned your husband is a gamer.
Ping times on cellular data are not going to be as good as land line based. You may get some good ones here and there, but on average its not going to be as good. I don't know for sure, but I would guess that gaming will use a lot of data.
Online college courses: is this video based? If so, then you're looking at increased data usage.
Good luck with your adventure. Hope you get everything worked out.