Yes it is possible to have your new partners name on more than one mortgage. Depending on your existing lenders 'criteria' with regard to status and income as to how they will view his/your application. I would suggest that you and your new partner make an appointment to see a mortgage advisor at your lenders offices to discuss the matter. At the end of the day this is ALL going to come down to your ex's agreement and your new partners finances.

Good luck.