Wife's Friend Started With

My wife's friend invited my wife and me to Pasadena for the Rose Parade and Rose Bowl. We all live in Northern Calif. They have been friends for a number of years. They hike together nearly every day. Catherine's husband has degenerative back problems and has little energy to do much of anything. He's in pain and on opiates. He sleeps a lot and is on a completely different sleep schedule than Catherine, He did not go to Pasadena. I had been around Catherine a dozen times in the last 5 years. She always made it a point to compliment my fitness and appearance in front of my wife. It got my attention and I didn't think it was meant for what I wanted it to mean. I must admit it made me fantasize. She is in her 50's, attractive with nice tits that you can tell sag when when wears a shirt without bra. She has a nice ass.  We stayed at Catherine's elderly parents home. It's very large and spacious. We attended all of the festivities and had a great time. Each morning we were there, Catherine set up the coffe at night befor everyone went to bed and I would get up at 5am and start the coffee while everyone slept. On the last morning there, Catherine met me in the kitchen. She had slept on the couch in the living room which was far from the bedrooms. She was wearing a semi sheer nighgown. I was in flannel pajamas. As I looked at her body I started to get hard. I was trying to be casual and ignore my arousal. I quietly told her I was going to go take a shower and walked down the hall to a bathroom. Catherine followed me and before I could close the door she came in and said "Let me help you with the shower". I wasn't sure what was going on. I told her I was ok. She asked if she could stay. I was hard again as I gazed at her nipples and looked down at her pussy. I threw caution to the wind and took off my clothes. My cock was at full attention as I got in the shower. Catherine put soap gel in her hands and began stroking my cock. She wispered she has wanted to do this but no more. My cock was lathered and feeling great. I leaned out of the shower and touched her small nipples. I rolled them between my fingers as she continued to stroke me. She stood back and asked me to do myself so she could watch. I couldn't take any more and shot on the shower wall. We stood there, water running looking at each other for a few seconds. It seemed much longer. Catherine turned around and walked out. I finished showering and went back out to the kitchen to have coffee. Catherine was sipping coffee with a heavy robe on over her nightgown. Over the past 4 months she and my wife have invited me to hike with them. When my wife if off doing other things , Catherine and I have hiked together. She has told me she hasn't had sex of any kind with her husband. She still has desires but doesn't want to masturbate herself only. She said she liked watching me jack off.  We'll see how we manage this. I want to help her and enjoy myself while helping her.