When I was about 30 I met a wonderful woman. She was the classic girl next-door; 26, 5'6', 125 lbs., and had perfect 34 B breasts. We spent a few nights together, fooled around with each other but had not yet had intercourse. One evening while we were in bed together, I told her that I wanted to show her how I keep my sanity that she had to take off all of her clothes and do nothing but sit between my legs and watch.
We both took off our clothes. She sat on the bed and I lay there with my feet straddling her. I put a little lotion on my hand and commenced to stroke on my 5' penis. I wanted her to see each stage of my arousal, and took my time. She sat passively watching me for about 15 minutes.
I could feel her eyes glued to my penis, but she did not appear to get excited. Finally I groaned and let loose a load of semen on her legs. With that, she leaned over pinched my nipples and gave me a deep French kiss.
She said, that is the most unselfish thing I've ever seen. Please do me now. She lay next to me and opened her legs to my hand. I slowly stroked her outer lips and realized she was well lubricated. About three minutes of fingering was all it took for her to have a crashing orgasm. I later learned that that was her first orgasm ever. That one evening taught me to be open and unashamed of masturbation.
We stayed together for several years and had all types of sex with each other. Many times if she was tired or uninterested in sex and I was ready to go she would start stroking my cock put lotion in my hand and lead my hand to my dick. As I stroked, she'd kiss me, hold me, and whisper come for me.
There's no reason to be ashamed of masturbation. It can be a shared intimate event.