OP, I would advise you to go to a GUM clinic ASAP and get the appropriate tests done to know for sure whether you have herpes or whether it is something else. They can examine you there for any visual signs and also take swabs to send for testing.
If I read your post correctly, you haven't actually been diagnosed with genital herpes in the past? You may be worrying over nothing if it turns out to be something much more commen (thrush in pregnancy is very common and can cause the symptoms you are describing).
If you do have herpes, the risk of infecting the baby in the womb (congenital herpes) is extremely low. If you were infected with herpes before the 3rd trimester (which you think you were infected before you were pregnant?), the risk of transmission to the baby during birth is much lower.
If you have an outbreak of herpes from 36 weeks, they can give you medication (acyclovir) to stop the transmission to the baby during birth.
It is important to tell your midwife of your concerns but she won't be able to diagnose you so you should also visit your GUM clinic.
Trust me, your midwife and the GUM clinic staff see this all the time every day and won't judge you at all. It is an infection just like other infections which they see day in day out.
I'm sure if you ask the midwife to put it in your notes to not discuss this in front of your partner then I'm sure they would oblige where possible, however if you are about to have a child with this man then surely he should be able to offer you support and reassurance, rather than judgement about this.