The Great Gatsby, that tangle back home

I'd like to know the meaning of "tangle back home" in this excerpt from the chapter Three of The Great Gatsby:

Her grey sun-strained eyes stared straight ahead, but she had deliberately shifted our relations, and for a moment I thought I loved her. But I am slow thinking and full of interior rules that act as brakes on my desires, and I knew that first I had to get myself definitely out of that tangle back home. I’d been writing letters once a week and signing them “Love, Nick,” and all I could think of was how, when that certain girl played tennis, a faint mustache of perspiration appeared on her upper lip. Nevertheless there was a vague understanding that had to be tactfully broken off before I was free.

Thank you.