I'm sorry this is happening for you. It must be confusing.
Firstly - I'm not sure starting a new relationship while the other one is in limbo is a good idea. I'm not judging. I legitimately mean I think it will be harder for you to work out what's right for you while you're in amongst it.
Secondly - do you want s3x at all? If yes, but not with your DH, that probably means something different than if you don't want s3x with anyone. Or as much s3x or whatever. But again, difficult to work through while you're around both of them.
Counselling might help you work out some of these feelings.
Some alone time - proper alone time also might help you work it out away from the sources of confusion.
There are ways to resolve competing s3xual appetites if that's the issue.
Also your DHs clinginess and dependency may be an effect of what's happening in your relationship instead of the cause. I don't know. Has he always been like this? If not, consider it. But again, counselling may help to work that out.
I'm so sorry this tumultuous time is happening.
I hope you can find a resolution that works for you and your family.