Everyone has heard that love is a delicate thing. It takes time to build and is hard to maintain; and sometimes, regardless of how hard both parties work at it, love does not always work out. The important thing, in this case, is knowing when it's over. It's important to be able to tell when you have fallen out of love.
It can be hard for someone to admit that he is not in love anymore, for various reasons. Whatever the reason, it is important to keep in mind that pretending you're in love when you're not is unhealthy. It can lead to unhappiness, bitterness, depression, and other serious health concerns over time. Also, the more someone puts off telling his significant other how he truly feels, the more it will hurt - so you're not doing you partner any favors.
There are many tell-tale signs that you are not in love anymore. Some are more obvious than others, but all point in the same direction. If you start arguing on a daily basis over trivial things and even the smallest arguments escalate into full-fledged bouts of shouting, it might be time to sit down and reflect on your situation.
Some other signs might be that you no longer feel physically attracted to your partner or feel much less physically attracted than before, you make excuses to spend less time than usual with your significant other, you get easily annoyed by being around your partner or having to come home to her, or you feel distant or disconnected from your partner, for whatever reason, over a long period of time.
None of the above mentioned happenings should be taken by itself to mean that someone is not in love anymore. Mood can affect feelings and that can fluctuate regularly. Also, there are many other factors that may contribute to those feelings.
One of the most tell-tale signs that someone might not be in love anymore is that there seems to be a large rift between the way he felt toward his spouse or signficant other when they first started dating and how he feels now. It is perfectly normal for the “flame”, as some may call it, to dim a little during the relationship. It happens to nearly everyone, and it means that the couple needs to do something new outside of their old routine - whether this is just getting out and going dancing like they haven't done in years, or going on a retreat or couples' weekend to spend more time together. However, if it has been quite a while since you can remember feeling the familiar flutter of excitement when you get to see your partner or a happiness to know that she'll be there waiting when you get home, it might be time to consider if you do still love her.