Female dog in heat living with a male dog

Question
My 6 month old beagle/terrier mix, female, lives with a 2 yr. old mixed breed male dog, who is much bigger than the female dog. We do not want to breed them, of course, but I am concerned about them living together with her going into the in-heat cycle.
My question is this: will she stay in-heat longer because she's around a male dog? And will the male dog go back to his normal behavior when her cycle ends?

Answer
Why not get her spayed?  It is better for the females health anyway.  Or get the male neutered.  No she won't stay in heat longer, it lasts about 3 weeks and happens usually every 6 months.  You need to keep them separated and be careful because males can be very persistent in mating and they can both break out of cages or even jump fences.  It's also stressful for the male while the female is in heat, many of them won't want to eat and they will pant and try to get to the female.  They can even mate through a fence or crate, so be careful in keeping them separated until one or both are fixed.