Is it wrong if it's consenual?

My situation is rare, but not unique. When I was 28, and living out of state away from my mother, my step-father was diagnosed with stage five melenoma cancer months after my mother and him married. With no family living close by, my mother became very depressed, and lonely while caring for my step-father, and a working a full-time job as a nurse.
Over the course of about a year as my step-father's condition worsened, we spoke over the phone frequently, and became very close. My mother would often confide in me her fears, and concerns about being alone, and i would reciprocate by sharing my frustrations about not being able to meet any woman. Eventually we starting sharing intimate details about each other's love lives, past and present, and a sort of sexual tension developed between us.
When I came home to visit that for Thanksgiving that year, my step-father was close to losing his battle with cancer, and there was something notably different between my mother and I. She was very nurturing, and affectionate with me, and during the evening while we were watching TV my first night home, my mother exposed herself to me, and she noticed my excitement, but didn't say anything perhaps to safe me any embarrassment.
Later, during the early morning hours, my mother showed up at my bedside in tears, telling me how she missed having some intimacy, and after listening to her for some time, she asked me if I was willing to have sex with her, and we would take it to our graves. I agreed to my mother's proposal and we ended up having sex that morning. As taboo as the experience was, we ended up enjoying the sex immensely.
The next morning we discussed what had happened, and we both agreed to continue our incestuous affair for the duration of my visit. By the time I had to return home, my mother and I confessed to each other we didn't want what we had to end, so I ended up moving home a week later, and we spent the next five years in a monogamous relationship living on and off together in an attempt to hide the nature of our relationship from family and friends.
As unatural, as many might categorize this relationship between us, we have grown quite accustomed to being intimate with each other, and no longer have any qualms about the taboo. I was wondering from a physcologists stand point, and from others, if we were both consenting adults when this incestuous relationship began, and we have had no pregnancies as a result would this be condemned by others since homosexuity is considered the norm today?

Personally I believe something isn't 'wrong' (define wrong) if it's consensual, though I'd add a caveat that acts do not just affect those engaged in the act. The question is whether those other parties affected by the act have any real entitlement to claim harm. For example, two consenting adults have sex, but one of them is married; I'd contend the aggrieved spouse is entitled to feel aggrieved and so the act was wrong. On the other hand, a brother and sister have sex, and society is outraged; society can f**k off, as it's none of society's business.

I'm in a situation where I am attracted to my lonely mother. I recently caught her with a married man and saw the whole thing. I love my mother and feel she is sexually starved, and she hasn't done well with relationships. I'm not sure how to move forward, it is hard to want something you can't have.

I agree with ctithe.

You were an adult as your mother was, so, yeah, I don't think it's wrong in the least. Agree with ctithe on the aggrieved husband.

I had read stories about incest beginning when the son/daugher was a kid, so there I ... do think there's... well, confusion for the kid and many times abuse. But at your age, don't see a problem at all.

If you are both enjoying it, it's your decision only.