You know I'm the last person to give relationship advice, given the way things are for me the last few months.
I don't know why it is men think they can't tell us stuff. I can only imagine that having their wives mad at them is very scary and must remind them of their mothers being mad when they were young boys. I mean, if he told you up front, you would have been mad but you would have gotten over it. Now you are not only mad, but you are also mad that he lied to you and feel betrayed, and wonder if he is trustworthy about other things. So even if you get over the thing, there is all that other damage that happened.
I also have noticed that husbands of at-home mothers seem to think that we are taking their money away from them. I know he worked hard to earn it, but I work too and I don't get paid for what I do. If he wants me to stay home, he needs to provide me with enough money to take care of household expenses, personal expenses (clothes, hair cuts, etc.), and some kind of entertainment as well as whatever the kid needs. Our consumer society only really recognizes personhood and authority as coming from having money, so at-home moms who have to ask for money and aren't gainfully employed are treated like a burden. I know that my husband resents giving me money out of his paycheck, not because he wants to deprive me of anything, but because he feels like he traded his time and energy to get it and he should have the full benefit of it. I understand his feelings, but that's not the agreement we made.
Anyway, what I do know is, you need to get control of yourself before you talk to him. It might take a couple of days. If he notices you are distant, that's fine, it's proof of how angry you are. If he asks you about it, you can say that you really want to talk to him but you are still in the yelling stage and would rather wait until you can talk without calling him names. Give yourself time to figure out exactly what you are mad about so that you can name it properly. Cry if you need to, but don't do it in front of him because most men don't get it when women cry out of anger. They feel manipulated and it makes them nasty. And let him know what the effect is on your marriage and what he needs to do to make reparations. Otherwise in a few weeks when life goes on, as it inevitably does, and something else triggers the same reaction, he's not going to understand that it was related and he's going to think you are holding a grudge. Forgiveness is a 2-way street, it only works if the other person repents.
I am assuming this isn't a marriage breaker for you, just a horrible thing that happened that you can get over if you both work at it.
addendum: FWIW, there were only the 2 original posts from Dawn when I started thinking about this. Health concerns are a big deal, too.
Forgiveness will come with time, assuming he repents and changes. Do think about what that means to you (he stops lying but openly takes steroids might have to be acceptable, you forgive the lying and accept that he isn't going to change the other because he doesn't see anything wrong with it). Forgiveness is not about feelings, you know, it's about behavior, and the feelings heal later.