Dating a woman who’s undecided between me and another man

So, here is my situation: I've recently rekindled things with an ex. Our break-up was smooth and we agreed to remain friends. We're often in touch and the physical and mental attraction that brought us together in the past hasn't truly worn itself out to the point that we've recently grown a lot closer to one another. The other day I invited her out for coffee and when I asked her if she was seeing someone she said she had been seeing this other man for nearly 3 months. Their relationship started as an affair and, even though she left her ex-boyfriend for him, they're not committed to one another yet. As a matter of fact, they haven't told each other "I love you" yet nor did they have the exclusivity talk. She said she was going to have the exclusivity talk with this other man as soon as she'd see him. He doesn't know that we've already had sex and I don't think she's going to tell him, at least not until she's made up her mind. Ever since we grew closer to each other, she said she's been into both of us a lot (apparently, she never truly forgot me) and needs time to work through her feelings and who to choose. What would you do in such a situation? Right now she's choosing indecisiveness, so how long would you wait before walking out or asking her if she's made a choice? Consider that I invited her to spend next weekend to my beach house and to go to Sicily with me this summer. I don't know if these plans, who she seems to be into, will help her make a final decision. Thanks!