Can't Stop Cheating On My Boyfriend

I've been with my boyfriend for two years, but I can't seem to stop cheating on him. It's not that I don't love him, but I have a compulsive need for attention and validation. Ive slept with multiple guys behind his back and feel guilty and ashamed, but I can't seem to stop.

I'm afraid of losing him if I tell him the truth, but I know I need to come clean..