The key question is whether or not
Revenue will consider your original property or your partner's property as your
PPR. Since you say that the latter applies that seems to be that but if there is any confusion contact
Revenue or an accountant/tax expert for advice. If your partner's property
is your
PPR now then your are subject to a clawback of and your own property will be treated as a normal rental property
as far as tax etc. goes. If you have been availing of the but the property is no longer your
PPR then you can no longer avail of this and must deal with the normal taxation of rental income as per the previous link. Even if it is still your
PPR and you are collecting more than €7,620 p.a. in rental income you cannot avail of the rent a room scheme and a stamp duty clawback applies. If the property is rented other than under the rent a room scheme then some portion of the eventual resale value will be assessable for [broken link removed].
Basically you should probably get independent, professional advice on this matter since making a wrong assumption/decision could be costly.