Don't give up because you have difficulty pulling the sail out of the water. The more you do it, the more you learn to use your body weight rather than just your arms, to get the wind to help you, and most of all, not to drop it and have to start all over again.
It's also particularly hard to balance in the low/no wind conditions people generally end up starting in, because you have to hold the sail up, rather than balancing it with your weight. Then when you get advanced enough to use a harness, that really saves your arms.
You'll probably find your DH gets just as tired, because being a man, he will have to take out the biggest sail he can lift, whereas you will take out the biggest one you feel comfortable with.
In terms of fitness, don't forget the whole of your back - v v important, and your abs, as well as arms and shoulders. It's endurance you need rather than strength, so train lots of reps with lower weights.
If you have loads of money, Neilsons do a fabulous windsurfing holiday in Vassiliki. Wonderful for all levels - and much nicer sailing without a wetsuit.