Trouble, we started 4some poly relationship once. I was 52, my wife 40 the other wife was 32. The husband wanted to go open marriage, so he could start having sex with an old gf. He picked us because I was older than his wife and he thought it would be a turn off for her and he would be free to do his old gf.
It didn't follow his plan. His wife fell in love with me, became friends with my wife. She and I have wild sex. She finally got tired of his bullshit. They had a violent relationship. My wife and I never fought, we talked things out. The other wife left her husband, moved in with us as a V occasional triad. It was very good, until about 5 months in she wanted more of me and to be exclusive and tried to split us up. It ended.
Watch the guy if he dumps his gf and wants more from your wife... just be careful.