Perfect Ending?

Lately I have been reconsidering the ending to my latest novel, Finding Father.  Most of my readers have told me that they like the ending, and several have said they would like to see a sequel.  I considered this a compliment and thought that it was a good plan to end a novel with the readers wanting more.  But recently a professional who read the book told me that I ended the story too early, that I didn't show enough of the romance, and that I left several of the secondary conflicts unresolved - in particular the tension between the hero and the girl's mother.

I know as a reader that I like to feel a sense of closure at the end of a novel.  One of my favorite books, Gone With the Wind, had a very open ending, with Scarlett and Rhett actually separating and Scarlett planning how she could win him back. But it is difficult to pull off an ending like that, and I don't pretend to be anything close to Margaret Mitchell in literary prowess. So it's possible that, in leaving my ending somewhat open, I was being a bit too ambitious.

On the other hand, I want my story to be believable, and in real life many difficult relationships never become happy, close, and loving. I've also read novels in which characters who spend the whole book fighting and hating each other suddenly fall into each other's arms in the last chapter. To me, this sort of pat, unrealistic resolution is worse than anything. I would rather read a book in which some tension and conflict remain at the end than feel that the author sacrificed truth and realism for a "happy ending."

So that brings me back to the ending of Finding Father. Can I find a resolution between Steve and Bonnie that is satisfying, but doesn't feel trite and contrived?