compulsive liar

i have just found out yesterday morning that my boyfriend of 8 months (i know this is not a long time) is a compulsive liar and has been kind of living a double life...i found out that he has been seeing me and his ex since xmas and she is pregnant with his child due in november......i know these facts are 100% true...i confronted him today and h flatly denied it all he even lied to a freind of ours about where we had been on friday night we stayed in he sed we had gone out n when challenged by the frind he sed i was with him while he was out n that i was losing the plot!! more seriously and sickeningly he told me he had a baby 10 yrs a go that died he sed he was in the royal marines posted in ireland when he got the news he has never been in the royal marines or had this baby????? he has even cried in my eyes about this 'baby'?????? i have had supisions about him since xmas but he always made me believe it was me goin mad seeing things that werent there.......i feel sick to the pit of my stomach ..... why do people lie compulsively even when they know they have been found out??? i would be glad of any advice.....he has also conned me out of quite a large sum of money

My advice to you would be to get as far away as you can.
Im sure he has been kind to you at times and you feel he is not all bad.
There is probably little point in confronting him, as he will quite clearly lie, to cover a lie and so on.
Myb/f is a compulsive liar, and has done very similar things to me also, and its been years of hell. Eventually you will question your judgement of everything and your self esteem will plummet. He needs help, professional help to overcome these issues.
Ask yourself, can you ever truly respect him, if he can do these things to you?
As you are 8 months into it, get out while you can, for your sanitys sake. Take this as a lesson, move on, and dont get sucked into any further abuse you will receive. He will probably beg and plead you to stay with him, but you will be in for more of the same.
You deserve mor. Ask yourself, what have you been getting out of this relationship? Do not be his rescuer or enabler.
Good luck to you

As you said, he is a compulsive liar. As doctor Moore mentioned in one of his articles about this kind of behaviour "Common Behaviors of People Who Confuse Love With Obsession". The guy is obviously has low self-esteem and desperately wants attention and acceptance. That's why he's seeing two people at once.

The only advice we all have for you is run away as fast as you can. It's not a healthy and normal relationship. You should care about yourself more than a jerk like that. I just got away from a similar relationship but thank God I found out after seeing him for 2 months. Whatever Dr. Moore described in his article, this guy fits all of the descriptions.