Cant Believe It Really Happend

My wife and i had moved in together with my daughter when she was 3 years of age, at that time we weren't married so we were just common-laws living together. We enjoy each other company a lot but not in a sexual way other than my wife, but my daughter who is now married got separated about 3 years ago where she and her husband did not see it fit to have discussion about their marital problems with anyone who could help them save their marriage which seem to be on the verge of either a divorce or a getting back together because they are close friends as she now lives with us. My daughter is one of the quiet type who will not gives detail about anything that she deem as private and she is one of the person who you will never get any information from that easily but that's something me and my wife have learned to live with. Let me say this though that since my daughter have returned home to live with us i have noticed some changes in her that i have never seen in her before, like sipping wines every now and then, and mainly going around noticeably without underwear around the house where she have a couple of loose dresses that she wore when she showers after work or when she's going to bed.
One night i was around my computer just messing around because i weren't feeling sleepy but my wife was out cold because of a long day she had which caused her to be super tired, i was going through the hall way that leads to the kitchen which would take me past my daughter's room when i saw a very bright light. After a close examination of that light which btw her room door were half-way opened i saw her on her phone laying on her back with her knees straight up with her legs spread apart and at that moment i were in full view of my daughter's vagina that i have only seen when she were a baby but not as a grown adult.
When i went to the kitchen and was on my way back i confirmed what i had just saw by steering into her room but only this time from a section of the hall way where she cannot see me, and while i were there steering i haved notice something that i wouldn't have imagined and that is a huge boner in my boxer that i had on at the time. I immediately hurried back to my computer before i was caught because it felt so taboo looking at her in the first place which i didn't expect it to make me get stiff but it also was a feeling i wanted to feel again without acting on it with that being a secret to myself.

A couple of night have rolled by when the situation have been sweeping by my memory when the same thing happened again which even to this day i cannot explain why she have been using the phone with the brightness of the light that shines straight down the length of her body while she used her phone but what i saw her legs spread wide apart i find myself steering at her clit that stood out from the angle where i was and when i saw that i was immediately got harder than before which caused me to wonder why am i having this feeling seeing my own daughter's nakedness?
After a couple of steer i was getting very nervous with a stiff cock in hand while i stood there and after a couple of strokes i had to relent from continuing because of a strong feeling of come was right there to be exploded and after i successfully halt it i witness when she got up and saw my shadow moved from behind the half closed door when she say 'dad is that you'? and i say yes i went and eat a little ice cream from the refrigerator.
Things got even worse after that night where i started to peak more often with every chance i got and one night when she was there she fell asleep in the same position but only this time the phone was down and her room light haven't been turned off and my nervousness immediately got the better of me when i tip toed quietly over her with her face covered with a towel she always used on her pillow with her legs spread wide apart with a clean shaved pussy and when i look at her clit i witnessed her vagina slit was getting wet as her juice was just starting to flow down her slit and i started to imagine if she weren't asleep and had lowered me to come closer for a better view which i did with a very stiff cock standing over my daughter... and after a long steer i used my index finger and slowly run it gently through her wet crease which i heard a soft moan and her body slightly tremble.
I immediately leave the room as nervous as a scared cat where i was starting to question myself about my actions and saying i can't believe i have done that. I still peak when i can but i am now struggling with the feeling which i am trying not to let it over power me to go further because even to this day we haven't talk about it where i only assumed that she might know i was there or maybe not.. who knows'!