Hi Jennifer,
It looks like you're, if I'm right, peaking. The frustration you're expressing is healthy. I noticed in this last post you answered a lot of your own questions (another good sign). From what I've seen from SO's after anger comes grieving and from there (over years) comes acceptance. Sometimes acceptance doesn't mean someone will stay together, but from what you've described it sounds good or as good as it gets right now. I don't think you'll be accepting this tomorrow or maybe even anytime soon, but your feelings and expressions have been right in line with someone who is coping with this rather well. Doesn't seem like it right now, I guess?
You're right about everything you said pretty much. The truth is when you're 18-19, 6 months is a lot more of your life than when you're a million years old like I am. Everything you're feeling is valid. I think your last conversation with your father was the best so far. Yelling or not, though not would be better I'm sure,

you said to him "Look, if you'd just been honest I'd most likely not have been as upset." I'm sure those words sank in.
I'll admit I'm sad about you leaving the house, but it is best to let your emotions cool down. The things about words and actions that are made out of anger or confession is you really can't take them back. It seems your father has dug his feet into the sand and he's accepted or is starting to accept that he's this way.
I think you should trust your mom manage your sister's affairs. You've said it already. You are 19 years old. You don't yet have the wisdom to make the right decisions as much as someone older than you because of you're a new born adult right now. Your wisdom at your age, to me is still frightfully (in a good way) AMAZING! So, I hate doing this, but I'm taking a chance here that my assumption is correct.
If I'm right the issue here has never been with your mom. It's been with your dad and his lack of honesty. So please don't pull your sister away from your mom's care. Your father is a big, huge fibber who didn't think about the consequences he'd put his children and family through by being a selfish so and so. Please don't get in the way of your mom being a mom. If she wants to send your sister to your grandmother's then ok, but if it's you then you shouldn't try to be her parent.
Here's a crappy part about growing up. When you tell people things and you're hot/upset. They knod and act like they agree. They do this to help you out and let you vent. Then later you find out they were like, "Well you had a point, but so did the other person." So I'm sure your grandma is not happy in the least about this, but I do think she's going to get her arms around this whole CD'ing thing soon. She's going to most likely not ever going to forgive him, but I think she will accept him if your mom does. That's a wisdom that I'm still coming to grips with. Looking at my elders (ya' know like Saint Valentine and Socrates) and trusting their decisions were good ones. I'm still a very emotional person and I get very p'd when I hear about something wrong. Then I end up getting all emotional thinking everyone's with me. I do this because I go to people, "I'm not over-reacting right?" and they go, "Nooo way! You are soooo right." Then I go off and I say, "Well?" and they say things like, "I don't want to get involved.", "You were a bit mean.", "I agreed with you too a point, but you took it too far." and so I'm left out there alone. Just me and my feelings. Why this long diatribe? Well, because I can see that your mom and even your grand mother are starting to accept this now. It's not like they are accepting him, but they've started to let reality sink in. You aren't ready yet and that's ok too. It doesn't mean, as I said earlier, that anyone is going to change their minds tomorrow.
Going forward life is going to be a roller coaster for everyone. Right now your father doesn't feel the guilt. He's got a wall up to protect himself. That wall, just like your wall, will come down. When his wall comes down he'll see how fatigued his family is, he'll regret the lies and deception, but right now that's not going to happen. Especially with his daughter telling him everything he taught her to do right is being thrown back at him. Eventhough you and your mom taught you how to react to lies he's not hearing it that way. Right now his defense is you're a child and if you're adult enough to judge him then get out of his house. That's way uncool and he's not winning any brownie points in my book. You're a great kid, but right now he's just not in a place to hear it.
So, I'll change the topic for a sec. The sexual side of CD'ing. Your dad's not going to tell you there's a sexual side to his CD'ing. Talk about gross. Would you even want to know? ick!!! I doubt you're going to tell your dad the way you kissed your boyfriend or where he touched you and that's most likely the way he'd feel about telling you. So you can read here about those who have had the sexual episodes with CD'ing (including moi), but I doubt he's ever going to be honest with you about that. It's one thing I can understand about him. Which I'm not sure says a lot?
You're right about him not being the man you thought he was, but in life that's a good lesson. Finding out this way is more than horrible, but the lesson is a good one. I know this song I'm about to quote is really for women, but I took a lot from it because of my dealings with men as a teenager and watching the lies they'd tell to girls/women and themselves. The line is "A man can tell a thousand lies. I've learned my lesson well. Hope I live to tell the secret I have learned, 'till then It will burn inside of me." - Madonna
Life bites when it comes to getting honesty from people in general Jennifer. This lesson, though one of the most difficult one anyone can face, is not right, hell to live through, totally selfish of your father, and more bad things, (I can't believe I'm typing this) but it's good that you've learned it. If I had a time machine I'd go back and help your mom catch him after your sister was born so this could have come out much earlier, but even that would have interfered with your destiny.
You're a great person. A true future hero who's best years for the world are yet to come. In years, I'm telling you I guarantee this big fibber will be someone that you'll one day turn to for advice. It may not be how to be honest to your family, but it may be something else heavy. When you do want his advice I promise you'll go to him because you want to and because you'll trust him again. What I mean is this phase is going to pass. Believe it or not soon (not sure the timeline, but you won't be 80) you'll see what life is and go, "Oh.. so you wore women's clothes. What's the big deal, you're my dad." On the other hand maybe you'll also carry these thoughts too, "I can forgive you, but the pain you put me through I won't ever forget."
Unfortunately what I'm also saying is something will happen in your life that will impact you and cause you much more pain and anger than what your father did. That's shite news I know, but this is a pre-amble to life young one. How you deal with this is paramount to how you deal with things in the future.
You're thankful for having the opportunity to vent. I'm thankful you've visited us and have posted something so open and honest that you will help someone forever. You're a big breath of spring air to the forum. I hope the tumultuous times you've experienced when you come back here in years from now you look back on as one of your first real trials of your new found adulthood. You're a great gal and a great woman.

Thank you so much for being here Jennifer. I mean it more than I think you'll ever know.
I wish you heaven!
Beauty