I haven't yet. I have 80% custody, and get pretty bored sometimes, so there are times I wish he would just come over and watch tv or something to keep me company. But I'm not ready to do that whole "Let hang out all together" thing yet. I feel like I need to much more serious before I get my kids invested. And for me, I feel like I just finally got single. I don't want to date around per say, but I don't want to feel committed either.

Ex on the other hand introduced them ASAP. It was way too soon. He moved her into our house the day after we moved out, so they literally can't spend any time with him without her.

Whatever you decide to do, make sure you keep spending one-on-time with your kid(s). I hear a LOT of, "He can never do anything with just us, SHE's always there." It's created a lot of resentment. Kids needs to feel #1, and they should. If you go over to the stepparent board, they disagree and think the parent/stepparent relationship should be first, but from what I've seen 1st hand with my kids and my ex-step-daughter, those kids feel rejected and replaced.