It's totally normal to have a pair of friends who are ~couple goals~ and inspire you and your partner to do fun new things together. But when does envy of other couples cross the line from casual admiration to bad omen? If you and your partner constantly compare your own relationship to others' in a demeaning way ('you don't treat me as well as Jake treats Ashley'), that's not a good sign. You should be able to appreciate a good relationship when you see one, without making a habit of using your friends' relationships as ammo in an argument.

When you're in a long-term relationship, eating pizza, watching Netflix, and passing out at 10 p.m. can easily become the norm. It's totally normal to go through sexual dry spells in a relationship, and that alone doesn't mean you're doomed. But if there's a prolonged period where there's no sex and no communication about the issue, that's unhealthy and doesn't bode well for the future. Also a red flag? What Threadgill calls "slot machine sex" — where one or both partners withhold intimacy and use sex as a power tool. Sex should never be a bargaining chip, period.

According to Threadgill, constantly disparaging your partner to your friends is one habit that you definitely shouldn't get into. It's OK to vent to your friends when you need emotional support, but if you're meeting your friends for drinks every week and always complain about your partner/relationship, that could mean you're just fed up and ready for a breakup.

Let's get one thing straight: you should never feel like you're constantly trying to impress your partner. Your partner should accept you for who you are (and vice versa), but that doesn't give either of you an excuse to just stop taking care of yourselves at a certain point. When it comes to things like fitness, hygiene, and mental health, the two of you should mutually support each other, not become complacent. "Lack of effort could indicate that one or both you are losing interest or are too comfortable in the relationship," Threadgill says.

Whether you're single or in a relationship, masturbation is a fun, healthy activity that will help you get to know yourself sexually. But there is a point at which your masturbation habits might be problematic — like if you would almost always rather masturbate than initiate sex with your partner. Having me-time is different than honestly preferring solo sex, so if this is a pattern in your relationship, it might be time to sit down (outside the bedroom) and have an open discussion about how to get your sex life back on track.

When you first start dating and everything is brand new, it's normal to lavish more attention on your partner than you might usually. The mythical "spark" can fade, but that doesn't mean people in LTRs should have to fight to get attention from their partner.

If you've gotten into a groove where one or both of you regularly feels like you're not a priority or that you have to fight with other activities or people for your partner's time and attention, you might want to have a serious conversation about the future of your relationship.

In small, well-communicated-about doses, jealousy is healthy in a relationship. But if you and your partner have a habit of blowing up over every small flirtation or trying to control your partner's actions or behaviors as a response to insecurity, that could mean your relationship has run its course.

"Control is a response or an antidote to fear," Threadgill says. Stop and consider whether jealousy is a problem in your relationship — and whether you think it's worth solving.

It's natural and perfectly OK if you sometimes disappoint your partner, because none of us are perfect. But if you're both in the habit of making promises ('I'll definitely be at your mom's birthday party!') and then breaking them, that's not healthy or fair to either of you. Relationships are built on trust, and even if it's about something small or seemingly insignificant, both of you should respect each other enough to keep your word whenever possible, as well as trust that your partner will do the same.

Arguments are a part of any relationship, but how you fight and resolve issues says a lot about how healthy or unhealthy your relationship is. If every fight follows the same, frustrating pattern, ending with threats (on either side) of breaking up, that's evidence that the two of you, at the very least, have some serious communication issues to work out.

Even though it sucks, not all romances are meant to last forever. Working through your problems together might seem ideal, but sometimes it takes some serious self-reflection to figure out if you even want to salvage the relationship. Just remember: if you feel unhappy or unfulfilled in your relationship, it's never too late to pick up the pieces and start again with someone new.