[chris (OP)]

Trinity got in touch yesterday to ask:

I am O- my husband is A+ so far our children are B- and O- is this normal? I didn't think we could have a B?

What do you all think?

[evan_au]

Patterns of ABO blood type inheritance are shown here (the lower phenotype table is easier to read):
https://en.wikipedia.org/wiki/ABO_blood_group_system#Genetics

You can't inherit a B unless at least one of the parents has a B or AB blood type.
There have been some cases caused by chimerism,   but most cases have a more straightforward explanation.

[Monox D. I-Fly]

So, is the B one not her husband's biological child?

[hamdani yusuf]

So, is the B one not her husband's biological child?

Most likely. Unless the child get novel mutation.
More reliable conclusion needs more complete genetic analysis to compare gene loci between the child and the husband.