Google Cytisine, buy Cytisine. You can get it in a product called Tabex on Amazon. Amazing stuff - helped me quit after many unsuccessful nicotine replacement therapy / cold turkey attempts.
Couples who choose to co-habit report lower sexual satisfaction than those who do not co-habit, but still higher than those who are married, as per the (paywalled) research article.
A commitment as big as marriage leads to almost all sense of dread leaving the relationship, unless it is deliberately and continously applied. I think that, at least partly, explains these results.