Originally Posted by nycindie
If I were you, I would sit down with all of them, and your wife, everyone together and explain that this is "grown-up stuff" that they won't completely understand, and they don't have to like it, but it is your personal life and one important thing they need to know is that your having a gf is about having more love in your life, not taking it away from them or your wife. I would give them space to voice their fears and concerns and address the ideas they have about what a family is, but really, they have to stop throwing tantrums and feeling sorry for themselves. There are kids out there who have much rougher stuff to deal with - maybe have a family "count our blessings" session every night before bed, and everyone talks about things they're grateful for. It couldn't hurt.
I agree with Nycindie here... I know as parents we want to put our kids first always, but so long as you're still taking care of them and giving them all the love, support and attention they need, there should still be room for you and your spouse to have the relationships you want/need in your life. You can take it slow, give the kids some time to adjust, but don't let them guilt you into giving up a part of yourself that makes you happy.