In reality estim is a highly enhanced form of masturbation. Jerking off is very good for you, both mentally and physically. There is absolutely no reason why stimming or masturbation should adversely affect anyone's conventional sex life. Indeed, it will help by maintaining our male reproductive organs in good working order. The docs say we should orgasm many times a month to keep the male prostate healthy, 27 I think is the magic number.
Show me a married man who does not continue to masturbate and I will show you a liar. Even before we wed I never concealed this masturbatory habit from my wife and I'd honestly recommend you don't with your gf. It's a natural function we should not be ashamed of, and explaining it in open conversation with our partners brings that special relationship closer.
In my case stimming is my own, *private* sexuality in which my wife plays no part, and neither would I want her to. We were just 20 when we tied the knot and used to bang like rabbits, but as you get older sex tends to move onto the back burner. I still deeply love and adore this beautiful woman as much as ever, but three kids and a lifetime later my needs are more regular than hers. So stimming is a better (and cheaper!) alternative to finding a mistress. She is completely understanding and fully supportive of my favourite hobby. After all, how could she be jealous of an electronic stimming box?
However, I DO NOT tell her that stimming fulfills my wildest erotic fantasies and takes me to another dimension of sexual heaven I never believed possible. That might be a step too far!