Can I date my roommate's girlfriend?

Nate writes, "I'm a 58 year old man, many years younger looking and more fit than your average 29 year old. I am not in a committed relationship yet but one is hanging in the balance. The problem is that my 40 year old male room-mate has met a woman, 41, who is drop-dead gorgeous and who is moving into a room in my home. She is falling in love with me, and I with her. I have created a distinct distance from her, agreeing to be loving but not to the point of intimacy. He, BTW, is an 'unavailable' sort. They're getting along for the moment but I foresee that she's going to be with me. The age gap of 17 years is a concern. I am mature, loving, decent, wise, and caring. She is lovely, sweet, intelligent, successful at what she does, and as conflicted as I am. What to do?"

First of all, I hope you are prepared for the consequences of stealing the girlfriend of your roommate. You will just need to find another roommate unless he is cool with the idea.

Two mature people can have a great relationship even with significant age gap

Regarding your falling for her, well, as you probably read on my blog, the number of such relationships is rapidly growing (and is not a concern considering that you look young and relationships like that have been there forever; the groundbreaking relationships these days are the ones when women at your age date younger men).

Now I would have also objected to the relationship, if say, you were 37 and she was 20. Yes, the age difference is the same, but at 37, a person is fully mature and has gone through a lot but at 20, almost everyone is pretty clueless. At the age of 41, this woman knows what she is doing, she has experienced life, heartbreak, love, and pain. Maybe she is not as wise as you, but she is no clueless teenager. So go ahead and give it a chance; you might turn out to be a great couple.