DEAR ABBY: My boyfriend, “Al,” and I have been together for two years off and on. We dated casually for six months before we decided to be exclusive. Unbeknownst to him, I was also sleeping with someone else, “Brandon.” Al and I had a fight and broke up for a few months, and during that time I slept with another good friend of mine, “Marc.” When Marc and I decided it wasn’t serious and moved on, Al and I got back together. I didn’t feel obligated to tell Al about it at the time, since “technically” I did nothing wrong.