I gambled with my girlfriend's money and lied about it

My girlfriend and I have been together for almost two years. She's responsible with money and I am too. Last week, I was dead broke but had this parlay with a bonus on Stake that I was absolutely convinced would hit.

I made up some bullshit about needing $100 for a work expense that would be reimbursed. She didn't hesitate to transfer the money. I feel like such a piece of shit typing this out.

Anyway, I placed the bet and against all odds, it actually hit. $5,000 payout on a $100 bet. I was ecstatic but immediately realized I had a problem: how do I explain suddenly having all this cash?

Instead of coming clean, I bought her a $1,200 designer handbag she'd been eyeing for months. Told her I'd been saving up for it as a surprise. She was over the moon, crying and everything. Meanwhile, I'm sitting there feeling like the biggest fraud.

I've put the rest into savings but I can't shake this guilty feeling. Every time she uses the bag and thanks me for being "so thoughtful," I feel worse.

The relationship is built on trust and I've completely violated that. Part of me wants to come clean, but I know she'd be devastated to learn I not only gambled but lied about it.

What started as a "harmless" lie has turned into this whole facade. I genuinely love her and hate that I've betrayed her trust like this.

I know the right thing is to tell her, but I'm terrified of losing her. I've stopped gambling since this happened, but the damage is already done.