I watched a couple episodes, but the woman I wanted to win ended up leaving the show very early, and I stopped watching after that.
Then I happened watch some of the show when it re-aired, and ended up seeing the same segment with the woman I chose. It was then that I realized, she probably wanted to leave after having her date with the Gerry. Just as I chose her, she could have her pick of any other older guy, without going on a show. So, she and her daughter probably pre-planned an "out" for her, so she could leave early if she wanted. And she used it.
Theresa is not someone I would have picked. She doesn't quite seem like she's got her act together. But, maybe Gerry purposely picked her because of that. He may have known he doesn't want any of them. But, the show paid more if he proposed and even more for the wedding episode and they financed the honeymoon trip. So, why not do stuff on their dime? So, he married someone who will likely give him the least problems when he calls it quits.