It’s good that you’re being honest about your situation — that’s the first real step toward fixing it. You already know what happened was wrong, but guilt alone won’t help unless you use it to guide what you do next.
Right now, you’re torn between comfort and emotion your marriage feels safe, but your connection with the other man felt exciting and new. That kind of attraction can make you confuse passion with love. But the truth is, no healthy future can grow from a situation built on secrecy and pain.
If you truly love your husband and there’s still something to save, focus your energy on repairing that. Be honest with him only if you feel it will help the healing process (not just to clear your guilt), and definitely seek counseling individually and together. You need space to understand why this happened what emotional needs or frustrations led to it so you don’t repeat the same cycle.
If, after deep reflection, you realize your heart isn’t in the marriage anymore, then leave before starting anything new. But don’t make a decision based on loneliness or guilt. Take time to heal, think, and rebuild your sense of self first.
For now: pause contact with the coworker completely, give yourself emotional space, and get support (therapy, trusted friend, or counselor). You can rebuild either your marriage or your life but it starts with slowing down, facing your truth, and making a choice guided by clarity, not chaos.