Dominick,
I understand what you are saying completely and I think it's very sensitive of you to ask for help instead of saying something that would hurt her feelings. I think the best way to approach this is to
workout together.
Make it both
fun and something that you both look forward to doing together. Try to make her see it as something more of a date with you than a grueling experience.
Compliment and encourage her each time she completes a workout and generally just make her feel good about her accomplishments. You could also
make healthy meals together and watch the extra lbs melt off. Encouragement is the key but do it gently with much respect.
Before I became as fit as I am now, I had gained some serious weight and my SO at the time never said anything to me about it. I wish he would have.
Good luck to you and please keep us posted!