My obedient girlfriend, who was only kind to me, was seduced and impregnated by the man next door

My obedient girlfriend, who was only kind to me, was seduced and impregnated by the man next door

I've been dating Yui for a long time. I'm an unsuccessful entertainer and I rely on her and she always supports me. Our nighttime activities are satisfying and there's nothing that would make her betray me. I love her...