Does my cheating wife need help?

We have been together for 31 years ( including 19 years of marriage). We married in 1996 and had a beautiful boy. The relationship had not been a smooth one but despite that we loved each other and, I thought, were fiercely loyal to each other. In 2003 my little boy found a foreign mobile phone under our bed. After many many lies the truth came out. My wife had been conducting a once a week affair with a man who delivered bread to shops in our local area. He lived out of the area with his own family and delivered once a week in our town. They had met at her work in 1990, flirted for a year or too and then met secretly in a country lane for sex. This relationship continued in public places and just three times at the family home, for the next 12-13 years.I went into traumatic shock and I spent the next three months trying to win her back amidst arguments,fights and very difficult times but in the process I had a very damaging nervous breakdown and lost 70lbs in weight. My doc gave me anti-depressants and I soldiered on. I am still on 40mg of Prozac today.

After six months we calmy discussed things and decided to stay together primarily for the boy but at the same time we would attempt at least to become good friends. In 2004 I decided we would move home because I felt a fresh start would give us a better chance of a positive future. I wanted seperate bedrooms because I was still very affected and felt that my own space would help me to get better. Things were still tough. There were less arguments but things between us were never affectionate and mostly cool. Very slowly our relationship turned into a business-like arrangement and I suppose we were okay but not great friends. Maybe once a month, after much wine we would meet for sex which although very hard for me initially it became easier. I suppose was a question of 'needs'.

In 2007 I discovered that my wife was pregnant with our second child. I was surprised because I thought that she was using contraception but she admitted coming off it because she was convinced that in time I would leave her if I ever recovered. I was a little disappointed but saw it as a positive thing and did not really have aspirations to meet anybody else or go anywhere (how could I being immobile) so I accepted it and carried on.

In 2010 I had a fall, ruptured tendons in BOTH of my knees and spent three months in hospital. The next 12 months I was having physiotherapy but failed to regain full mobility without the use of crutches or a wheelchair over a long distance.This seemed to bring us slightly closer. I arrived home from hospital and had to sleep in our living room because I could not get upstairs. Things were okay she was caring for me and our little girl was growing and we both adored her. Our son was maturing into a young man and was very supportive of my disability.

The sleeping arrangements made it tough for a family to enjoy their living room/lounge so we had an extension built on the house so that I could have a ground floor bedroom with a bathroom. This happened in 2014 and my moods got better as I had my own space, a specially adapted bathroom and this gave me a more positive approach to life.

Towards the end of 2014 my wife had started to become very easily irritated in general and her attitude towards me had become rude, abusive and impatient. I managed to cope but arguments were starting again. We had a weeks holiday away at Christmas and that was okay. When we returned I noticed that more and more she was spending a lot of time upstairs in her room. When I commented on this she told me that she had discovered Words with Friends on Facebook and was becoming ''rather attached to it''. I did not really worry until things became crazy shortly afterwards. Every possible opportunity was spent upstairs playing this game. Things came to a head a week before my 50th birthday. We had a blazing row. My little girl came downstairs at 8 in the evening not in her nightdress but in her day clothes. I went crazy and shouted upstairs to my wife who , should have been getting our little one ready for bed but yes you guessed right she was glued to the laptop. The row was the worst for years and I suddenly realised that there was a possibility that internet chatroom sex or infatuation could be the problem, even though it accompanied a facebook community game.

The next day my wife had to attend a seminar for three days a few hundred miles from home so we would not see each other for three days.
While she was away I investigated her facebook page and discovered somebody on her friends list who frequently communicated with her and I found out he lived just round the corner from the seminar.

Whilst on the seminar she rang the kids but we did not speak. On her return I quizzed her about this guy on Facebook and after two days of turmoil I discovered through reading their internet chat and her admission that they had spent a couple of hours together in her hotel room one night. The sex was unprotected, consequently I went into mild shock and spent the next 24 hours trying to work it out. We were there for the kids so how come she would endanger herself meeting an internet acquaintance at a hotel which would bring all our lives into question.

It's now three days since my catastrophic discovery and I have realised that, surprisingly, I still have love for her even though most of it is because she is my kids mom. The laptop has been destroyed and she has changed her cellphone and has promised that it was just a one-off and it was never going anywhere because of the kids. We also have a large mortgage together and I am disabled. The problem I have now is believing anything she says after phase one which was one set of lies after another, 11 years ago. Her behaviour even today is still very cold and distant. She says she has not communicated with this guy for two days.

I am on tranquilliser tablets from my doc and am just about coping. My son and I have asked her to get professional help she has agreed but she is such an amazing liar that I'm finding it difficult to believe her willingness is genuine. She may be just playing for time until things calm down then resume her internet/cellphone relationship and plan their next rendez-vous.

I have not cried as much as phase one but I could still fill a pale/bucket with tears shed these last few days.

I would welcome anybody's comments, advice, recommendations or even psychiatric diagnosis of her and the situation.