Avoiding paying interest

Q: While I was studying at university (in the UK) I regrettably took out a student loan due to my lack of deen at the time, now I have come to realise that this was totally impermissible and wish to make amends.

According to the terms of the loan, I do not need to repay the loan if I earn below £17,775 per annum. The loan will be written off if I do not earn above this threshold after 25 years. I can repay the loan (plus interest) and make taubah but I feel very uncomfortable with this. My other option, which I am fully prepared to undergo, is that I continue to earn below the threshold for the next 25 years. I want to know:

1. Whether it is permissible to deliberately earn less in order to avoid paying any interest?

2. Whether I should repay the loan (through voluntary payments) but not the interest?

3. Whether I should simply repay every thing and just make taubah thereafter?

Husband not interested in having children

Q: I want to know about azal in Islam as my husband don't want to have children from marriage up till now, which is 8 years already. He don't want children  for the next 5-6 years and is insisting that I take family planning medicine but I dont want to take it because it is affecting my body badly and I get sick very fast from them. What is the right of the wife in this situation? Should I live with him or separate?