It can be tempting to get back together with an ex. When you run into one another after time has passed – after you've had some space and time to grow up and mature – all of those feelings and that chemistry can quickly come back. But just because you're both single and there's comfort there doesn't mean you should necessarily get back together.

Dr. Gail Saltz, a psychiatrist, psychoanalyst and contributor to The "Today" show, says there isn't a one-size-fits-all rule when it comes to deciding whether it's right to get back together with an ex. Here she offers six signs that getting back together with your ex might not be the best idea.

1. If it's out of loneliness
According to Dr. Saltz, people often get back together with an ex because they are lonely, which is not a healthy reason to get involved.

"People are propelled back into a relationship because something is going on currently that's distressing," she says. "People think of getting back with their ex because it's easier to look back to the past and find magic in it. The memory gets smoothed over as opposed to the sharpness at which it occurred."

2. If you haven't worked on the underlying issue of your breakup
A relationship usually ends for particular reasons, though they might not always be evident to you. For example, you might have an attraction to being treated badly, and so you tend to date guys who treat you poorly.

"It didn't work because you have a story that made you attracted to that person in the first place, but it wasn't a healthy attraction," explains Dr. Saltz. "If you have not worked on the underlying issue of what drew you to them, then that person isn't a good choice for you," she says.

It's important to analyze what drew you to your ex in the first place, so that you don't continue falling into similar dating patterns. With awareness and some work, you'll be able to decide if being with this person is a healthy decision or simply a bad habit.

3. If you don't respect one each other
"Often someone becomes an ex because you just can't get along and the arguing has gone on to disdain and contempt," says Dr. Saltz. "If you left feeling contempt and having no respect left for your partner, that's hard to come back from – even if it may have shrunk since."

If you have a real disdain for someone, you'll continuously put them down, she says. It's not repairable.4. If your reasoning isn't genuine
If you're considering getting back together with your ex for the sake of your children, for financial reasons or because you haven't found anyone else yet, these are not good enough reasons to romantically re-engage with an ex, says Dr. Saltz.

"I'm all for saving the relationship," she says, "but if you already left and put your children through the trauma of divorce, saying your child still wishes you'd get back together – and it's purely for that reason – that is not a good reason."

If you have children with your ex and need help with your finances, and that's the main reason you're considering getting back together, why not simply pool your resources together as a family instead?

Finally, "If you think: 'I'm just going to settle,' that's not a great way to go into a committed relationship," says Dr. Saltz. "It's in your perception. You shouldn't get into something if the reasons aren't genuine."

5. If you're not compatible
Sometimes people are waiting for some sort of magic love bullet to bonk them over the head, but that only lasts so long in any relationship. Sometimes you convince yourself that you're compatible and that you have a lot in common with someone until you spend enough time together to realize that's, in fact, not true.

Don't settle for someone whose personality doesn't complement yours.

6. If you can't let go of the past and aren't willing to work at the relationship
You can't keep hanging onto the past. If there are certain things about your relationship that have to be discussed in order to move forward, then do so, but don't keep the other person in your life just because you don't have closure.

"If you can forgive, it can work," says Dr. Saltz.

Once you decide on what you need to do to make your relationship work, be prepared to put in the work required, which, according to Dr. Saltz, most people aren't willing to do. If you and your ex are not on the same page, this is a clear sign you should not be getting back together.

"Generally, people give up too easily on relationships," says Dr. Saltz. "They expect the relationship to make them happy as opposed to them making themselves happy."

The idea of getting back together with an ex and trying again is often a really reasonable one, as many people jump ship without making the effort.

"A good relationship takes a lot of work," says Dr. Saltz. "The only person that could ultimately make you happy is you."