I really like what Wii has said. Because even with a wedding ring & vows - there are no guarantees that he will stay. Every one of us here knows that well.
I think you believe that Marc is the glue that has kept you together the past few years - & you know you are about to lose the glue. But that does not mean you will lose Gabe.
Personally - I would not ask him for a commitment even though that is what you really want. Because you seem to sense (& you know him better than we do) that the asking will make him run. But actions speak louder than words. Instead of a forced confrontation - why don't you work more on creating the life YOU want with him. The life that revolves around the 2 of you as a couple - not the one that revolves around Marc. You need dates, walks, a special treat - things you did when you were younger. You don't really have to spend a lot - go out doe ice cream or to the movies. Slip him a love note in his lunch. & I think he will begin to do the same for you.
Believe that he will stay, not that he will leave.
I have hesitated to advise you about this lately because I want the same thing from Josh - the vows, commitment & the wedding. But, unlike you, I don't live with the feeling I am going to lose him. I know that he committed when he bought the house with me. And the way we talk about the future. And as much as I'd love the wedding - he just does not - but that's the compromise I'm willing to make - because the relationships is great otherwise.
When my marriage ended - I learned the hard way that the more you try to hold onto someone & force your own agenda - the more they pull away. That is why I believe that if you drop the reins but keep the atmosphere friendly & loving - you will have a better chance of achieving harmony.
Gabe may be afraid if recommitting because he failed the first time. I think Josh is afraid after seeing the effect of divorce on me. But for whatever reason - you & I are in the same boat. But I choose to see the good in in & make the life that I want with him.
Personally - I don't think Gabe is going anywhere. But if he does - there was probably nothing you could have done about it other than what I suggest. If the atmosphere is not fraught with your fears of him leaving but with the joy of your loving life together - it's a place he's not likely to want to run from.
Let it go! Live one day at a time. And stop basing your entire life's enjoyment around what one man does or doesn't do.
And remember that if the worst were to happen (in your mind - that would be him leaving) - well you've already survived that. And a vibrant girl like you would pick herself up, dust herself off & go on!
