

TL;DR
Send your Monero from RetoSwap to another wallet from where you use it. Do not use it within RetoSwap for payments. Is that what it boils down to? Then I would like to remind you that in practice it makes sense to use two wallets. One for receiving and one for sending. The one for sending will be replenished by the one for receiving. https://monero.town/post/5701064
So: stick with Monero. It is a common misconception that swapping back and forth makes sense. If you want to store value, you should store it in the more secure Monero and, if you need to use BTC, exchange the required amount into BTC at the time of payment.
When exchanging BTC for XMR, it is a necessary evil that you have to use the BTC. But once you have exchanged them for XMR, you are on the safe side.