AITA for confronting someone I thought was a close friend and FWB about a bunch of lies that came to light recently?

I have been very close friends and FWB with someone for 4 years now. This past year has been tough for him. His business started to decline and because of the extremely rainy winter he didn’t work much. He needed help and asked for help with the promise in writing to pay me back.

The last seven months we have argued because of the money as he made choices that cost money rather than finding other work to supplement his income. I needed the money paid by now which he knew and has only made one payment since last November. The debt is a combination of money loans and use of my credit card. He plays sports and goes out to dinner and to sporting events. Last week we had a long nice talk and came to some great understandings because I’ve been struggling financially because of him.

Then as he was leaving the next morning he told me he was going camping for the 4th with his son and family. I asked how he could afford to go if he had no money and hasn’t paid all his bills this month and why he wasn’t trying to pick up odd jobs. He ignored that question.

My friends did some snooping without my knowing because of the financial struggles he has caused and because he had gone to my home two days ago and turned off my power causing my security system to go out so he could go inside my home without my knowledge. I still don’t know why as I’m visiting my kids and not home.

Turns out he was away with a girlfriend for the weekend instead. Posting hotels and dining out and all sorts of things. They left for their trip the same day we just spent the night together. I don’t believe he planned on me finding out and was going to continue as things were. I’m guessing he was lying to her too.

AITA for confronting him and stating it is unfair for him to be doing all these things and he hasn’t worked for two weeks or paid me but once over the last ten months. He lied and said he must have been hacked on his social media account. Then admitted it because there were so many lies that came to light in the last few days, including the entry into my home.

We got into a huge fight and I told him this has to be handled legally now because he has been lying about his finances and not paying me among other things. The judgment would ruin his business because it is already struggling and that’s why I delayed doing anything but I don’t know what to do anymore and I honestly cannot continue to carry his debt and had to borrow money, sold concert tickets that were a present for my birthday and other things so that I could survive financially his month because of his debt.