The first question that you need to answer for yourself is whether you need life insurance on your husband. If you didn't have any life insurance and DH passed, could you live off your earnings and existing assets (taxable, tax-deferred, etc.)? If you are FI or RE then generally the answer will be that you don't need life insurance. If DH is still working and you could not survive without his income then the answer would be yes, you need life insurance on DH.
The second question would be if you do need insurance, how much do you need?.
For now, let's assume that you don't need insurance. The next question would be what is the overall return the policy is providing. You can get an idea of this by taking (the cash value at the end of the year divided by the cash value at the beginning of the year plus 1/2 of the premiums paid for the year) -1. If that "return" is pretty good then it might make sense to keep the UL policy, and the insurance is a bonus. This might be the case if it is an older UL policy.
For example, I have an old whole life policy that currently provides a ~5.2% return plus the value of the insurance coverage, so I keep it.
You mention guaranteeing a 4% draw. Usually policies have a guaranteed interest rate. If the policy has a guaranteed interest rate of 4%, it may be worth keeping, particularly if you need the insurance. If you don't need the insurance but can reduce the face amount of the insurance to reduce the cost of insurance it may also be worth keeping.
If you have a need for insurance the UL policy may be your best bet, depending on the crediting rate you are receiving and what they are charging you for insurance (referred to as cost of insurance or COIs) and expenses.
EvaluateLifeInsurance.org will do an unbiased analysis of whether you should keep a life insurance policy for about $90. Depending on your situation, it may be worth the cost.