Hello Lovely,
I'm sorry it took me so long to get on the boards and read up on your situation.
LR is correct. I'm in the same situation that you find yourself in. I'll PM you little more in-depth look into my heart, but I wanted to give you a few pieces of advice to think on.
When I feel that rock sitting in my throat and my gut is twisting in knots, I ask myself a few questions (out loud, if no one is around

).
1) Does it mean my partner loves me less if she loves another?
2) Does her loving another mean she wants to replace me?
3) Does her loving another make me love her less?
As others on the board have said, it's okay, normal and good to have feelings and emotions. (If you didn't have any, you would be a shell of a person.) The key to remember is that you shouldn't react without first asking yourself what those feelings mean and where they come from. Words and actions can be apologized for, but the damage is done. These are wounds that heal, but always leave a scar.
I've read that you said your relationship has gotten much better after you both decided that it was okay to have multiple loves in your life. I think you will find that if you allow people to be able to be whole and complete, they will also be whole and complete with you.
Build on that love you two have. Spend lots of time talking and being real with yourself and each other. Now is the time to build the solid relationship that you and your husband want. You are on the right track, Lovely. Keep your mind and heart open, be true to yourself, and communicate with your husband, and also with Mary.
I have a lot of respect for you, Lovely. I'm here if you need to talk. PM LR if you want/need to chat to me. I'm working tons of hours, and have lots of things to get done in the next three months, but I'll be there if you need me.
Peace and love,
Maca