Sometimes two people genuinely give the relationship their all and they finally come to the conclusion that parting ways is the best and healthiest decision for all involved.
One or both of the partners are selfish. They prioritise their own needs and wants, and disregard, neglect, or minimise the requirements of others. There always has to be some caring and compromises by both parties for a relationship to work.
Love is a verb. It is something that you actively do. If one or both partners neglect to show or make loving actions then sooner or later, the partnership will likely fizzle out.
Marriage requires commitment and compromises to be made. Unfortunately some people just aren’t cut out for matrimony but they do it because they feel that’s what’s expected of them. If you are someone who is happiest when single, then it is unlikely that marriage will work for you, especially if you are just doing it because that’s what people do.
Some couples are just not suited. They may have incompatible personalities, interests, expectations, lifestyles, or tastes. Differences can sometimes be papered over during the dating phase, and the initial passions of love sometimes distorts a person’s viewpoint, but once the couple are living together under one roof on a day to day roof, any differences will eventually surface, and sometimes they are irreconcilable.
Some people just aren’t cut out for monogamy biologically. They are never going to be faithful to their partner, so marriage probably isn’t for them.
People change over time. sometimes couples grow apart because they each develop in different ways, or they progress at different rates of time. Over the years, a partnership that was originally compatible becomes incompatible.
sometimes the marriage dies because the sex life disappears and without the physical intimacy, the couple lose their bond. It depends on the dynamics of the particular partnership, of course. Other factors, such as age for instance, can also play a part in breakups.
Some relationships are always destined to burn themselves out. A romance that is hot and passionate in the early days, may be too intense to continue indefinitely. Passion can turn to arguments and excitement can become instability.
A relationship needs hope and optimism to keep going. If one or both partners lose their faith in the relationship, then there is a good chance that they will fall out of love too.