Married wife gives sympathy to friend

Some time ago when my wife was in her 40s (she'll be 60 this year) she had a brief th8ng with a friend of ours. His wife had left him and so he'd come round to ours for sympathy. Well I was at work mostly. But he would come round and I thought nothing of it. But after a few weeks I have to say I got bored hearing about this friends state of mind. My wife would talk about him a lot and away at work I got to thinking how much talking about his problems can this guy do. And I guess I started to worry. was my wife being naive and was this guy trying to hit on her. That evening I asked my wife about it and she said no its fine. He just needs a friend to listen and be sympathetic. I asked if anything was going on between them. He said no and anyway he wasn't her type. But as the weeks went by I got more and more uneasy. And I asked her again. In fact I got quite upset and we ended up having sex. I noticed she put her legs high up which was great. Got great penetration. I came right out asking her if that's how she did it with him. She said no. I don't do anything with him.
But he kept coming on round. I asked her what they did . She said they normally just took our respective dogs for walks. Sometimes in the fields by us and sometimes in the woods by his place. Alarm bells rang then. She went to his place. So I decided I would take a day off work and see what happened. The next day I drove off in the morning but parked up in the estate up the road and walked back to ours and hid in the bushes opposite the house waiting for him to arrive. And sure enough an hour later he turned up, parked his car and went down to the back door. There are fields behind our house. He didn't have his dog with him. Funny I thought. Anyway I took a circuitous route to the fields behind our house and waited. I figured they'd have a cup of tea first which gave me time to try and guess where they would go. And time to position myself discreetly. There is a nice secluded spot in some trees a bit off the usual ramblers track. My wife and I had been a lot over the years. Sure enough half an hour later I heard voices and I took a peep. Yep it was them. No dogs. I heard them push through the undergrowth to the secluded grassy area. They had stopped talking. I could see them clearly as they undressed. They'd even brought a blanket with them. I had an instant hardon seeing my wife naked outdoors. Even after kids she had a great body . Lovely hairy minge 36dd tits. Red hair pale skin. He was tall and skinny. She was only 5' 2". His cock was long and thin. Mine was short and thick. Anyway they lay down on the blanket and started making out and I could hear telling him to be careful and to pull out as she wasn't on the pill. And then he entered her wet swollen pussy and started pumping her and I could tell she was enjoying it by her low moans.
After a while he decides he wants to fuck her from behind and so he pulls out while she gets on all fours. I could see her love juice on his cock.
Then he enters her again and begins to fuck her faster than before. And she can obviously feel him about to cum and in between moans and yes fesses she tells to be careful and soon after he pulls out and i can see his hot spunk fly over her arse cheeks and up her back