Unyielding Focus

You gain a plus 1 to CON or INT. 

You can maintain concentration on two spells at once. Once per turn, you can choose to make a INT saving throw, DC: 8 + Both spells casting levels. On a success, you can use the effects of both spells regardless of casting times. On a failure, one of the spells ends at random. 

You can use this feat a number of times equal to your proficiency bonus.