It's hard to know what to do here. Were it me, I would struggle the same as you not to just jump back in. My thoughts:
1) If she's vacillating at all (ie one day wanting to be with you and the next saying she'll let you know if she wants to), then I wouldn't commit to working on the marriage again. She will not make the effort this marriage deserves until she's worried she's losing you.
2) If she's been sincere, apologetic, and has been chasing you, then I'd date her. I know a person needs to be wary of her intentions, but what more can she do to you? Can you survive if she isn't actually committed to the marriage? If not, then you need to get there before trying with her. If she cheated again, could you kick her to the curb? If not, then you aren't ready. It's only when you don't need her that your in the place where you can chance this again.
3) Do you know your own worth? Does she know your worth? It really rubs the wrong way to be second choice/fall back plan. But sometimes you really do need to swallow your pride. It happened....and she could never come back without it looking like you were the second choice. But, again, if you know your own worth, you know you aren't second fiddle to anyone and won't tolerate being that.
4) If she really wants to work on the marriage, I would lay everything on the table...if she strays, she's gone; you aren't second fiddle to anyone, if you are just her security blanket she shouldn't come back; you are interested in a fulfilling, happy marriage, if she isn't willing to work towards that, then don't come back. You can make the rules, but only if you are truly willing to live without her if she's not in it. That's why starting at dating may be the better plan. See if there is a foundation to build on.
That seemed rambling to me. Hopefully some of that made sense. I know she has a lot to prove, but she can't prove anything if you don't give her a chance to. You be the guy she would be crazy to not want...and if she doesn't want you, then you haven't lost anything.
You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer
