Some people need to learn the difference between privacy and secrecy.
Secrecy will kill trust in a relationship. I am very open to those I am in relationships with, about other potentials in my life. I don't go into awkward details, or give private information, but there are no 'secrets'.
I expect the same from people I date. If I don`t get that, bye-bye.
The reason secrecy is so damaging, is because it prevents others in the relationship from making informed choices. What your husband is doing, he may feel is ok, because its nothing 'firm' only the 'beginnings'. In his mind, if he actually set up a date and had something concrete, then he would tell you.
That is a bit of a slippery slope, he probably does not realize. So he might think it is 'much-ado-about-nothing'.
You can explain to him, ( and make sure you live up to it.) that you don't want details, or to know when he is 'busy' chatting, you would just like to know when he is thinking of 'looking'. That being informed of a intention, is all you need.
Once the differences between secrecy and privacy are sorted out, those that are offending, tend to find it a old habit that dies hard.
Someone who has always lived this way, will not break such a habit overnight. It is up to you to decide if it is worth working on.
There is a lot of debate about what is secret, and what is just private. My experience tells me, that those who just believe in privacy are not ashamed to say so. They explain upfront what they will, and wont give.
They dont act weasel-y. ( New word, I own it.)