You can only claim medical expenses paid by you, or someone who is a spouse or a dependent when the services are provided or when you paid for them. Only the amount of expenses that are greater than 7.5 % of your AGI (Adjusted Gross Income) may be deducted and only if you Itemize Deductions (if you pay mortgage interest, real estate taxes, charity, high medical and dental, unreimbursed employee expense) and not use Standard Deduction. TurboTax will ask you the right questions to make sure you get the higher deduction.
Now, if your boyfriend claims you as a dependent on his return, then he may claim the medical expenses provided they exceed 7.5 % of his AGI (Adjusted Gross Income).
Please see:
Rules for claiming a dependent
What kinds of medical expenses are deductible:
https://ttlc.intuit.com/replies/4774889
[Edited 1/24/2018 9:18 AM PST ]
