OCC ji, asalaamu alaykum, long time no see kaurhug
The opinions around divorce and spouses differ between Sikh groups.
If you're not Amritdhari, then not many "rules" apply to you anyway.Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/questions-and-answers/38596-question-about-converting-sikhism-married-person.html
Sikhi doesn't say too much about marriage and divorce. It's really up to the individual. Case in point, the Anand Marriage Act they're trying to get through in India, some Sikhs want a divorce clause, yet the Top Brass at the SGPC are saying once you're married, always married. Yet Sikhs still do get divorces.
Generally, I think the opinion is that divorce is an absolute last resort. Short of domestic violence, it is incumbent upon the spouse to honour the sanctity of marriage and try ones best. Else, why bother with marriage at all?Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=38596
The spouse can be a non-Sikh in mainstream Sikhi. In groups such as AKJ, the spouse must be Sikh.
I hope that helps!