My husband has distanced himself from the family for 6 months with a repeated pattern of coming home at night anywhere between 10:00 pm -1:00 am allunder the guise of "work". He has not come home on three occasions until the following day. Currently, he is no longer coming home during the week, and showing up to be with the kids on the weekend. This pattern has been going on for 2 weeks now. He cuts off all communication during the week.

Is this abandonement? What constitutes abandonement by law?

I think it depends on what you want to accomplish but that really isn't abandonment in any legal terms. That is just something that you have to determine how much of it you are going to take and what you are going to do.

The law doesn't like getting involved in anything domestic unless it involves bruises or clear cut child abuse.

Abandonment, as grounds for divorce, would be a TOTAL disassociation from the family for a period. That period would be defined by local laws.

What you describe is not even close to abandonment.

But you have to decide what you want to do. Do you want to divorce him? If so, your state may have a no fault divorce law. Or there may be other grounds. Best to consult a divorce attorney.