Desire for Daughter

This is a confession about the love of my daughter's tits. I am an 81 yo man, married to a sexually inactive wife. My daughter is 44 years old. She got married about 11 years ago and gave birth to two wonderful grandchildren, Her husband got out of the Army and was training to work for the FAA on radar systems but while in school in Oklahoma City, he decided to start seeing a 15 yo girl and got caught by police, in a parking lot with the girl, at 4 AM. After being arrested, child porn was found on his cell phone. He was sentenced to 10 years in prison and my daughter handed him divorce papers. She now lives with my wife and I along with the kids.
She is a beautiful girl that could easily pass as for a 20+ yo college student. Soft facial features, natural beauty not requiring make-up to enhance, a few extra pounds, most of which she carries in her breasts. She does have the shelf in her lower stomach caused by repeated pregnancies. Her boobs are very large, 44DD , but she was complaining that she was needing to get a larger cup size. We have no issues with nudity inside the house, not to sat we are nudists, but the occasional nude body is not unusual. I get to enjoy her big titties about once a month or so. They hang off her chest like two large teardrops. Her tits and areola are pale, her nipples pink. Her areola are about 2" in diameter with eraser-sized nipples. They do not get too long when excited.
I suffer from Erectile Dysfunction (ED) so any kind of penile penetration is not possible. Also, since I can't get an erection, I can be excited but not show it. I can look at her tits and I want to feel them up and lick and suck her nipples. She doesn't seem to realize my desire, thankfully, as if she did, she would become a lot more cautious about being seen. She does not wear a bra in the house and if she looks over my shoulder at something on my computer screen, that big, soft tit pushes into my arm and shoulder.
I have wondered if she could be bi. I don't think so, but I believe given the right situation, she could become bi. She has several friends with big tits. One of her best friends moved to Colorado who has a FF cup and is bi. She is now separated from her husband and is coming back east to attend a seminar and visit friends. She will be staying here for two weeks. She worked as a phone sex operator while they lived here but stopped when the company she worked for started ripping off her income. I know that she approached my daughter about having sex but that was while my daughter was married. The situation is now different and it's possible they could get together. Anyway, that two weeks will be extra exciting for me with two sets of huge tits in the house. Love to think about a F-M-F session but not too likely. My wife would throw a fit even though she is not active. I love her very much and at this time in our lives, I will not divorce her, but would love a relationship with our daughter.