Is she cheating? Why am I losing trust?

[Wakeup]

There is always a bit of a decline in every long term relationship... life gets in the way afterall of us just ****ing all day long. I didn't read where the sex has drastically declned either, backup.

Besides: Most would leave if sex has DRASTICALLY declined (if they're not codependent and afraid to leave that is) whether cheating is involved or not.

No need for complex math algorithms to come to that conclusion ;o)

[bcgirl]

My girlfriend and I have been 'dating' for 4 months, (I am 22, she is 21) but have been seeing each other for about a year.

At this stage of a relationship, it is still considered young and sex shouldn't be sliding that drastically. Especially two young 20 yr olds. The fact that she is holding off on sex now is a red flag. In fact at this stage in your relationship, the sex should be improving. You two are more comfortable with each other, and the insecurities of your performance in bed as well as your body image naked slides and your less self conscious...therefore making sex more enjoyable and thus should be having better sex. Sometimes a cheater holds off on sex because they are scared to potentially pass off an std to their spouse (if they have had unprotected sex). Their guilty conscious tells them they shouldn't f*9k their spouse until their pap smear comes out negative. Anyhow, i see more red flags than not. Dump her and move on.

[ttylox]

It always baffles me how men can be so completely ignorant of when they're obviously being manipulated by a woman. Maybe it takes one to know one - as I used to play this harpy bullshit game myself - but really, you don't need us to spell it out for you. She's using you. She knows how to do it too, it sounds like - since you're still hanging on her every word. I bet that phone call when she thanked you for letting her stay and telling you she loves you made your entire day... I bet it validated you for a while. She knows that! She knows that it doesn't matter if she comes into your bed with sex bruises from another dude as long as she bats her eyes and sweet talks you, you'll give her a safe place where she can rest or be taken care of - even if she's not giving you anything real.
Maybe her other boyfriend is more independent - maybe he doesn't compliment her enough or pay enough attention to her - so she needs to slip you in there to supplement.
I'd tell you to close the door, block her calls and make a clean cut - but you seem like the kind that needs her more than she needs you.