Relationships aren't always easy. In fact, sometimes they can be extremely hard. But the thing about relationships is that it's a joint effort, and supporting one another through everything (both the good and bad) can contribute to how successful or unsuccessful a relationship can be.
For someone who has been through a lot during my 20 years on earth, I know how it feels to feel trapped in your own mind, but having a supportive significant other can take some of that heavy weight away because now, you atleast feel like you can confide in someone.
But something I have failed to realize in the past is that confiding in someone doesn't mean putting all of your emotional baggage onto them, it's about moderation but most importantly about understanding that both of you can be there for one another without expecting for the other to immediately fix all of your problems or drop everything to cater to yours when they may be struggling themselves.
You see, I understand how hard it can be to be someone's shoulder to cry on 24/7 because then, you don't have enough time to cater to your own emotions and mental health. It can get tiring, draining, and can make you question if all aspects of the relationship will be spent picking up the other person's broken pieces, but know that there are ways to support your siginficant other through their worst days without it draining you and altering the trajectory of your days.
You may not believe it, but a simple text telling your loved one that you're thinking about them, all while encouraging them to keep their head up will really help lift their spirit. Never neglect your significant other when they are struggling, but If you arent able to be emotionally available to them in that moment, communicate to them that you will still be present. Couples tend to fight over bad communication, and I know in my experience I have mistaken some of those things for complete absense, when in actuality, my boyfriend just couldn't be emotionally available to me at the time because he was going through things as well.
We have to be compassionate within our relationships, understanding that there are two people who will both have bad days sometimes. Simply reminding your significant other of how loved they are by you won't necessarily take all of the pain away, but it will show them that their pain can be alleviated through love. Embrace your loved ones when they are hurting, and pay attention to the little things so that you can show them that there is indeed light at the end of the tunnel for when they begin to doubt light exists at all.
Being a good boyfriend, girlfriend, husband, or wife requires good communication, but it also requires a great deal of empathy, compassion, and care, so always remember to support them throughout it all-- the good, the bad, and the ugly. Those bonds you establish then will grow stronger and stronger until they are unbreakable, and the relationship will prosper as a result.