Sitting on your bed all alone on a Saturday night, endlessly bored and way too single. It's like you blinked and your sister from another Mr. is poof gone, off on some crazy adventure with her new boo, while you're on an adventure with Tony Stark and the rest of the Marvel crew... or whatever your Netflix show/movie of choice is.

It can be so difficult when your best friend gets into a relationship. And it can be even more difficult is it's a relationship that you don't approve of. In the end, it's their decision. Here's a quick guide to help you identify and move past all these aching feelings.

Recognize why

Before you can accept your BFF's relationship, you first have to identify why they bother you so much. Even if you think you know why, talk it out, write it down, be sure to fully hash out your issues with this person. You may realize it's simply a jealousy thing, or there could be a totally real problem at stake.

1. You might dislike their S.O.'s behavior towards you.

• Maybe they have a bad attitude and don't know how to stay positive about anything other then you're BFF.
• Do they ignore you when you're around? Nothing is worse than your best friend's S.O. not wanting to be best friends with you too.

2. You may disapprove of the relationship itself for some reason.

• They aren't who you would pick for your best friend.
• You feel that they are not good enough for your best friend - no one like a dead-beat.
• You feel that they mistreat your best friend, and maybe they do... (hint: tell your BFF you feel this way asap; and maybe consult a trusted advisor, therapist, or parent for their advice on the issue beforehand)
• Your best friend might complain about them to you—It's crazy how common this it, BFFs are constantly airing their dirty laundry and it's so easy for you to soak up their emotions. Since you're not there for the make-ups, those emotions might stick around for a little longer.

3. You may feel left out or envious.

• You might not have a significant other yourself, and you kinda wish you did.
• You feel like your friend no longer has time for you due to the relationship.

By understanding why you don't like your best friend's significant other, you can start to identify how to take the problem head-on and it will help you determine whether your feelings are warranted. You should always look out for your best friend, and that doesn't mean disliking their S.O. because you can't spend 48 hours together on the weekends anymore.

But if you are genuinely concerned about your best friend's well-being in a potentially abusive relationship, that's a different problem entirely. Pull her aside and talk to her about the situation, don't over-step but if she opens up and admits that she might be being abused, encourage her to leave the relationship and seek out help.

And like I said, maybe you simply feel jealous. It's easy to feel left out when your best friend, who usually spends her weekends with you, is now swooning over her new boyfriend. If that's the case, focus on yourself. Maybe even head out on your own date or two. Who knows, you might be double-dating with your BFF soon enough!

Get to know them, whether they like it or not

Even if you can't stand the sight of him or her, get past your initial hatred and try to get to know them. Plan some time to hang out with them either alone or with a group of friends. Maybe, you've only been seeing them when they're with your best friend so you may dislike them purely because of feeling like a 'third wheel.' But, what if you're feeling like they don't like you either? Offer up some group plans that they can't refuse, here are a few ideas:

1. Throw a Superbowl/World Series/Award Show/Bachelor watch party and personally invite both your BFF and their S.O

...and let them both know how much you'd appreciate their attendance. Get to know them while they're there, everyone has something in common. You've just got to find it.

2. Invite their S.O. camping with the rest of the friend group (if they're into it)

What better way to bond then getting down and dirty with the great outdoors? Come super prepared to swoop in with anything they need they may have forgotten (hint: bug spray, toilet paper, an extra blanket)

And if your best friend's S.O. is a private person, they might come off as unlikeable simply because they're quiet.

Take your time to get to know them. They may even learn to appreciate you even more because you didn't give up on them, just like your best friend didn't.

On the other hand, if her S.O. is outright rude to you, something's up. Talk to your best friend about the situation and let her know you're not comfortable. Try to work out a plan with your BFF that'll lighten the relationship between you and her S.O.

Remember your friend's happiness is most important

Even if you still don't see why your best friend is dating them, you should let your concerns subside if you see that your friend is truly happy. In the end, that's what matters the most. Focus on how her eyes sparkle when she sees a text from her S.O. or you see her smile when her S.O. comes into view. While it may suck, there's a point when you need to realize that ultimately, her happiness is your happiness.

And if your best friend's S.O. still bothers you that much, give them some space. You don't have to force yourself to spend time with them. After a while, the honeymoon period of their relationship will cool down, and by then it'll probably be so routine you won't mind them at all anymore.

But..... however, it's still a totally different situation entirely if you know that your friends S.O. isn't treating them right. Maybe you've heard some gossip, or you've seen a few suspicious text messages on his or her phone, or you make plans and she cancels because their S.O. is... what's the word, clingy? If you have reason to think that the SO might eventually hurt your best friend, is being manipulative or emotionally abusive/physically abusive, don't stand by. Find out more, and if you have reasonable cause, let your best friend know that something's up, and don't let her be naive about what abuse looks like. Tough love is true love, and she'll thank you in the long run.

Don't forget to preserve your friendship

All too often, friendships crumble amid the whirlwind of a new relationship - be careful not to let your friendship fizzle out.

Give them some space, but once the new relationship normalizes, schedule some girl-time and never make her feel like she needs to choose between you and her S.O. Make sure she knows that even though you are not spending as much time together, you are always there for her.

It can be hard to make a friendship work when a new S.O .comes into the picture, but make an effort to reach out to your friend and things will be all right.