It's hard when you feel you have no one to confide in in your day to day life. For me, I felt a lot better when I started being more open with my friends. For me, hiding was not an option, and I certainly didn't want people to think I or my partner was cheating on the other if we were seen out and about on dates with other people. I don't necessarily go out of my way to tell everyone, but my closest friends know and it makes a huge difference. How else are you expected to meet people if the whole world thinks you are off the market?
You mention that at the moment things are a bit one-sided with your husband getting more dates than you. Are there any practical reasons for that? Do you guys have kids that you tend to spend the bulk of your time with? Does he work somewhere where he meets lots of people? Sometimes you need to look at the big picture when opening up a relationship - it's not always enough just to say 'well, we're both free to date so let's get on with it', but sometimes you need to work together to grant each other equal opportunities to date and make connections. It's unlikely to ever be exactly equal between you all at any given point in time, so if you are wrestling with feelings of envy, then know that that is often quite normal. As long as you are getting the chance to put yourself out there and meet others then it helps. If there's a deeper imbalance at play, then it's easy to become frustrated and resentful.
Anyway, welcome to the forum. I too opened up my relationship at my partner's request (although I had been in open relationships before), and I remember in the beginning that it was all a bit of a struggle since I had no one in particular 'on my radar' so to speak, and would have been happy with just the one relationship. After a while I did find lots of reasons to stay in a poly relationship for myself though, and it became less about doing this for her happiness and more for my own. I think that's really important. It needs to work for everyone involved, so if it isn't, then don't be afraid to speak out!