Is it possible to avoid a fatal attraction? Well, the answer would have to be no, because the truth is, there may always be another partner who is a better fit for you, no matter how committed or devoted you are to the current partner. There's always a chance, a possibility that time will pass, you will change, you will grow in a different direction and a different you will find someone else more suitable, more attractive, more desirable.
And so, when it comes to fatal attraction, it's almost impossible to avoid it. All you could do is really work on your relationship. Remember to continue dating. Remember the three As, attention, affection, appreciation, and hope that your relationship will grow and change in that, in that that new relationship will still be satisfying to both of you.