I have been in your situation. Here are the pitfalls as they occurred for me. First, I formed a very close, intense attachment to my Dom. I realized pretty quickly that all those little things over the years that I'd told myself I didn't need...I needed them. Being liked and enjoyed just as I am. Being told once in a while that I'm beautiful - other than hearing once a year "you look nice". (Gee, thanks.) Feeling appreciated. As a result, I told my husband I wanted a divorce. Commence the mayhem. Suicide threats...emotional blackmail...all of it. Then, he found about about my Dom (all my fault - I was careless). Now it wasn't mayhem...it became sheer freakin' insanity. Every threat he could think of. Constant need for me to 'try again'...all under his terms. I ended things with my Dom (biggest mistake of my life) and made the effort. It didn't work out. I won't go into the gory details...but my mild-mannered, laid-back husband has been insane ever since.
Don't put yourself through that...and if you do, make DAMN SURE your husband will never, ever find out. No one can know what another person will do under certain circumstances.