how could i do this

I've been with and loved the same man for the last 4 years. I love him very, very much. He has severe anxiety problems, and we've gone from medicine to medicine over the last 3 years together. It's been trying, heartbreaking, dramatic, and yet I still love him more than anyone on this planet.

Yet tonight...It wasn't enough to stop me from doing such a heinous, dirty thing. I gave a BJ for cash. Because it was wrong, terrible, and easy to do. I hate that I'm such a terrible person for doing this to you. I've cried beside you as you slept for the past 3 days, going through my own downward spiral of depression which ended with this tonight.

Everything I say sounds like excuses, and I don't want to live.