I got scammed by an 'online girlfriend' into sending Bitcoin — can I recover anything?

First: what happened to you is not your fault. The people running these operations are professional manipulators, often working from scripts refined over thousands of victims. Shame keeps people from reporting, which is exactly what the scammers count on.

Practical next steps in order:

1. Preserve evidence. Every chat, photo, voice note, wallet address, and transaction. Export the chat history before anything gets deleted.
2. File reports: IC3, your local FBI field office, your country's national cybercrime unit, and the platforms where contact occurred.
3. Get the destination wallets traced. For losses in your range, a serious on-chain investigation is justified. Firms like Nethertrace handle exactly these cases.
4. Talk to someone. Victim-support groups exist specifically for romance-scam survivors — the AARP fraud network and the GASO (Global Anti-Scam Organization) are good starting points.
5. Do not engage with any 'recovery hacker' who DMs you. You are being added to victim lists right now.

From the chain side: $42k in BTC over four months will have moved through a predictable laundering pipeline. There's a reasonable chance the cash-out exchange is identifiable. Whether anything is recoverable depends on jurisdiction, timing, and whether the receiving exchange responds to law-enforcement freeze requests. Pull every transaction hash you can and start the trace as soon as possible.