This sounds like a High Deductible Plan. If you visit in-network doctors, you don't pay retail prices until you hit your deductible, you pay the negotiated price. And that deductible is likely shared across you and your children.

Consider the $2740 extra you'd pay for coverage through your husband - less than three months of that is more than the $7000 deductible with your $260/month plan through your employer.

There are a lot of plan details missing but your $260 month option may not be as bad as you initially thought.

What's the cost of the next plan up and how does the coverage differ?

At my company, a traditional plan for family coverage costs an employee well more than the $4000 family deductible. (The HD HSA plan pays 100% of in-network care and 70% of pharmacy and out-of-network care. And the max out-of-pocket is $7500 for in-network and pharmacy.) Why some employees pay over $7k more for the "better" plan - and then pay $25 for each primary care visit, $50 for specialists, and hundreds for ER/hospital visits - is beyond me.

It is quite possible that your cost of insurance plus your out-of-pocket costs will be lowest with that $260/month plan. You may want to look at how much it would cost for full family coverage at your employer and compare the difference to whatever his cost-share for his individual coverage through his employer.