1.他比平时明显地更加关心和关注你，尤其是那些他以前没有投入过任何注意力的方面。其实这是他内疚的表现，因为在发生“变心”的最早阶段，其实是一种潜意识的补偿心理，这样主要是让他自己觉得好受点儿。

2.莫名其妙地开始给你买礼物，可他本身并不是一个浪漫或者爱这样讨好**人。

3.他突然变得喜怒无常，经常没事找事，无论你做什么他总是能挑出毛病。这是人在心虚状态下的反应，他潜意识里觉得自己“错”了，所以想证明你也“错”了，这样在心理上他就会产生一种“扯平了”的感觉。

4.他的行为会让你心生疑虑，可能你也说不清到底是哪里有点不对劲，但就是觉得“怪怪的”，这个时候，不妨相信女人的直觉吧！一般都非常准~

5.只要你一“反击”有时候甚至只是撒娇装装样子，他就马上提分手，根本没有心思和你沟通，也不会提出任何解决问题的方法。

6.只要你要离开他一段时间，比如出差、旅游之类的，他就会显得莫名兴奋，当然不是那种“欢送”般的感觉，而是变得比较情绪化，比如不停地帮你准备行李，对旅程过分关心，或者表现出夸张的沮丧。

7.变得冷冷漠。变得不爱说话，也不爱交流。但是期间并没有发生不愉快的事情。

8.品位突然发生变化。例如开始听和以前不同的音乐，看不同的电影或书籍，甚至会关心以前全然不想理会的事情，比如娱乐明星或猫猫狗狗之类的事物，

9.突然开始自信。如果你们并没有发现有其他事情激发了他的自信力，那么从“男人的魅力”这个方面得到了心理满足很有可能是个原因。他可能通过某些方式提升自己的形象，以此来弥补内心里面的空虚感或是不安全感，从而感到自信起来，但是这并不代表着真正意义上的改变，只是在表面功夫罢了！

10.start to pick on you and say "I hate this kind of thing" directly.

11.his behavior is more selfish than usual, he only thinks about his own feelings and needs, without considering your feelings at all.

12.he becomes more possessive or jealous than usual, constantly checking your phone or computer to see if there are any suspicious messages or activities.

13.he starts to avoid intimacy with you, saying that he is tired or busy when you want to hug or kiss him.

14.he becomes overly protective of you, always worrying about your safety even when there's no need for it.

15.he starts to make excuses for not spending time with you, saying that he has work-related things to do but in reality he's doing something else.

16.you notice a change in his body language around other women; he might lean towards them more often than before or find excuses to touch their shoulders/arms/hands frequently while talking with them (it may seem like an innocent act but trust me it could be a sign).

17.the way he talks about relationships changes; instead of discussing the importance of commitment and loyalty as before now suddenly they become distant memories which don't matter anymore accordingly from what I've seen after observing some men who had been experiencing such behaviors due possibly because they have found someone else who makes them feel wanted & needed!

18.your friends start noticing these changes too! They might tell you that your partner seems different lately – less interested in conversations involving personal matters related directly back towards himself?

19.there are moments where the guy tries really hard NOT TO BE FOUND OUT by engaging into acts meant specifically designed so no one can ever suspect anything bad happened between him AND another woman—AND THIS IS WHAT YOU'RE SUPPOSED TO SEE!

20.at last:if nothing else works out yet still feels right then most likely this person will probably end up being unfaithful just because THEY CAN'T HELP IT OR RESIST THE URGE WHEN THEY FEEL THAT WAY!!