How do i treat these low life prossies who are making a play for my husband..advice please?

I'm distraught. I'm a 39 year old woman who cannot conceive. I married a 24 year old last year. We seemed to have been soul mates and time was running out and my clock was ticking. I was worried about age but he ued me he was ready for committment. Since we married hes slept with 3 woman, the latest being a 21 year old brat from next door. She lives with her family and is so brazen she used to sunbathe topless in the back garden and shes huge on top..and actually a part time swimwear model. However, shes slept with him and i told her mum. Her mum just said he must have led her on as he mustnt have been happy with me and that he sweetie didnt chase him. I'm distraught and angry but I love him. The girls so brazen, when i called her a slag, she said at least hers were still ripe and that he wanted to play wtih real for a change ( I'm a flat 32AA and a size 18, but i cannot stop eating). My husband says he stil loves my body and what that cow said was so hurtful, but I blame her, what a tramp. Now i make a point of walking by her house and snogging my husband infront of her. Please dont say its him, i'm not leaving him. I love him . I'm not givnig up on my marriage. Also in bars , as hes quiet good looking, stupid tramps are always flirting with him.. it annoys me but he does not invite them, they are just loose...and surely they are. In our local one dirty 20 year old little slag came up to him and asked him how did her bum look in skin tight trousers...infront of his wife, me. He was disgusted and told her to buzz off, I poured a drink on her and my husband grabbed me and snogged me to prove his love. So its not him, its them, i saw it for myself. He says all he wants is to have a baby with me and i'm going to try ivf. Tell me how to keep those sluts from ruining my marriage? Honestly in the local (where he goes for a pint everyday while i'm at work just to get out, he says the barmaids simply wont respect hes married and are all over him like a rash. He said he made 3 mistakes and wont be doing it again. How should i treat these low life prossies?