Hubby keeps me a secret.

So my friend pointed this out, on my husband's social media. I am no where to be seen, there isn't a picture of us on our wedding day, with our daughter or anything. I first I didn't think much of it. Until one day he lets me use his phone. And he got a message from a girl on his Facebook. Now usually I wouldn't snoop but when a girl sends him a message with a heart and what not. I kinda had to take a peek. There wasn't anything but teasing and what not in it. Only when they were getting to know each other he doesn't mention me or our kids. And I don't know if it's my hormones or what but I feel very upset about it. But when I spoke to him about it, he told me I was overreacting and that he "didn't want to scare his friend away by saying he was in a relationship" i don't want to be in a relationship where I feel like I'm kept hidden or a secret and I don't know how to talk about it with him, without him ignoring me or changing the topic. Help??

Edit; he wants me to also tell you all that my Facebook says "single" but for two reasons 1: I just made a new one not even two weeks ago. 2: when It did say married with "SO name", he hid it. It didn't show up when you clicked his name or looked at his bio. But everyone knows I'm married with the pictures I post of our family. And most people I have on Facebook are close family and friends. I wouldn't care if his Facebook said single but the fact he didn't tell his friend if what upsets me the most.