NI online payments - which option?

Hi Since losing my husband 9 years ago in 2015 I've lived off an RAF widows pension and have worked part time (although I'm not currently working) Because I work part time I've not had NI contributions deducted but I have made some voluntary contributions. I should get my state pension in 4 years when I'm 67. I still have gaps which I hoped to pay via the new online system however - the questions about when I intend to stop paying NI have stumped me. It is unlikely that I will work full time again but there doesn't seem to be an option for my situation. If I did work full time again I would obviously pay NI - so I haven't actually stopped paying already (I just don't meet the criteria to pay) Which option should I choose? Also - when my husband died aged 54 he had worked continuously since age 16. As his widow am I able to claim any of his credits towards gaps in my own record? Thank you

Hi Inula,
Regarding the payment of National insurance you are trying to make please could you give us a call for the best advice and assistance, I have provided contacted details below. 
Number  0300 200 3500
Text Relay  18001 0300 200 3500 (Text Relay)
Overseas  +44 191 203 7010
Open
Monday to Friday: 8am to 6pm Closed on Saturdays, Sundays and Bank Holidays.
National Insurance: detailed information
Regarding your query about claiming your late husbands national insurance credits, there is certain credits of national insurance that can be transferred between spouses Such as Home Responsibilities Protection or Parents and carers credits.
However for us to give you a more precise answer it would be best for you to speak to an advisor on our helpline. 
Thank you.