You’ve dated the same man for 14 years, had two children with him, lived together for five years, and he’s cheated on you and fathered a child with the other woman. I know you’ve forgiven him and moved on — but has [i]he[/i] moved on? Getting over infidelity takes two, and he has to understand and communicate why he did what he did, and if you had a part in his straying, what that part was, and what’s changed for both of you so you can rest assured that he won’t cheat again. It doesn’t sound like any of that’s happened, and instead, you’re looking for a ring to signify some kind of change because you don’t feel it in the relationship.
You’re looking for another level in this relationship that doesn’t appear to exist — unless things change.
I’m not sure how old any of you are, including the kids, but you have to make a decision about whether or not to stay together for the sake of the kids or move on and find Mr. Right.