If you have the money to support two horses, I would suggest just leasing your current one out, but if you cannot find the best possible home for your current one, making sure that if the buyer goes to sell it they would allow you to buy it back before looking at anyone else who may want it:)
If you have enough time and money to own both then try it out for a few months.If it doesn't work out the sell or lease/loan the one you have now.If you don't have enough money try working at your barn so you don't have to pay half/all of your board.If you don't have enough time maybe consider giving up a sport/hobby so you will have more time to do this.Hopefully this helped!
It really depends.
Do you have the money to take care of 2 horses or not.
How much do you not want to let go of the horse.
If you do a lease/loan do you know how much they are ganna pay you and do you have a contract made up.
And then there are a lot of other factors that you have to think of