Discovered boyf has been cheating on me with his ex - felt angry but today feel really sad :( HELP!!!?

[Rosie]

Well ive suspected for some time & when asking him if he was cheating he always said no & it usually caused a row!!
Found text msgs to his ex about a month ago - most were sexually but he promised he hadn't slept with anyone except me since he'd known me since last september!!
What a fool I'll tell u!!

He left his phone on the table while we were in a club fri (3am) - came up with a girls name & I answered it!!
Discovered he's not only been having regular weekly sex with his ex of 2 years, they've been trying for a baby for 2 yrs (she already has two kids of her own & is married!!) she left her husband for him a while ago ( I believe theyre now back together) he's been driving over to hers & sleeping with her often ( he could never be bothered about coming to my house!!) he would sleep with me one night & then sleep with her the next, he's also living with his parents at mo & they have allowed him to have both of us staying over & just acting like it's ok!!!!

Found out he hadn't joined Facebook to find old school friends he'd infact been messaging his ex while she was away on holiday with her kids & husband in America!! WTF!! he apparently texts her everyday - sometimes I don't hear from him up to 4 days!!!!

Discovered he'd also joined two dating websites & had been lying to me about msgs!! Stating they were Facebook msgs to mates relatives - works out that evening he wanted me to leave early in order for him & his mate to meet these women!! Again all sexual msgs & hooking up dates/times

So this is where things turned around!!!!!
I edited his dating profile - sent msgs to all his contacts telling them he was a total dirtybag, lier & cheat!! I then woke him up, told him I knew everything & to get out of my house - He tried to tell me he loves me and was trying to cuddle me....I asked him to leave.

He tried to call me early hours sat eve/sun morning - I suspect he was drunk, I didnt pick up the call. His ex text me throughout Saturday afternoon stating he had been ringing her asking to see her!! I feel gutted!!
What type of person does this to someone their meant to love? He wanted me to fall pregnant and said if I did he'd marry me!!?
Proper twisted!

He text me yesterday lunchtime saying sorry with a kiss at the end...I didnt reply.

My friend said he is testing the water and he might be trying to worm his way back into seeing me however im not sure...I think its obvious I was always his number 2 and hes not that bothered.....

I dont think he feels guilt having been with two women for 9 months and not blinking an eyelid at the disgrace of it!!

I feel very upset that he hasnt asked to meet with me to discuss it all...even though he seems to be chasing his ex and wanting to see her....
Before he left he said he had been waiting for something like this to happen for 2 years....he'd have another girl on his arm by the end of next week....
As he left he tried to hug me but I pushed him away and told him to just go....
How can someone do this to someone else? He knew my ex had cheated on me and he was always asking if I was seeing other people, getting jealous and winding me up about it...I can now see why.....