is it normal to have relations with my brother

My wife and one of her brothers used to always be grabbing at each other's privates and chasing each other around, but they were involved in a passionate incest relationship, that went on for years, on and off. They actually had a series of several affairs, with gaps of a year or so in between. They too would sometimes kiss on each other. They did wrestling and fighting sometimes too, even right in front of their parents, and this would naturally get them sexually aroused. Besides fucking, they would also jerk each other off, or she would give him a blow-job. He did not care to go down on her much, but another brother did. He finally ended up knocking her up, when she was twenty, which is what led to us getting married. There parents did not mind them fooling around, jerking each other off, but did not want them to "go all the way". Onanism was okay tho as long as they boy pulled out of his sister in time and did NOT shoot his sperm inside her. But they were not always successful in getting apart in time. Sometimes they would get so carried away with their fucking that he would cum in her. She and her mom both tried to get him to use condoms, but he refused. He did not like them. She went on the piull for awhile at age 16, but she had trouble with the, and had to stop using them.