I think you should go with your husband. He probably wants to see his son and, if you don't go, another rift may get started.
As Nonogran has said, you can get to know his new partner while father and son have a private chat.
I hope the reunion goes well. Did you like your stepson before the rift?
Nicola Sturgeon’s husband Peter Murrell re-arrested over SNP finances.
Nicola Sturgeon’s husband re-arrested
To think that London, or anywhere else for that matter, does not belong to any one demographic