When my boyfriend and I have sex he says I feel different and thinks I've had sex with someone else but I haven't. We've been sexually active for over a year and just recently having the issue. What could be going on?

Sounds like he is trying to make excuses or shift the blame for something, is he having sexual issues when you have sex ?
Could perhaps he have cheated and is wanted to accuse you to make his cheating justified if you find out ?

Do you notice any difference?

I kind of do notice a difference. But I honestly haven't cheated. I notice e sometimes I get super wet too. Like more than normal. We have been trying to conceive too, so not sure if that has an effect or not.

There are many factors that can affect how our vagina feels, smells, etc.

Just a few things that can cause changes:

Weight gain
Weight loss
Diet
Exercise
Arousal
Hormones
Playing with toys
Manual manipulation
How often you've been having sex
How vigorous penetration has been
Etc.

Another factor may also be that you are looking for differences.

What changes have you made in preparing to conceive? Are you eating differently? Taking better care of yourself? Exercising?

I haven't really changed anything because I try to be healthy on a regular basis. He keeps saying that it's never felt different before so something is going on and he is dead set on me cheating but I really really haven't and no matter what I say or do he will not believe me and now he doesn't want to be intimate with me at all. It's killing me inside. If I had cheated I wouldn't be so bothered by it but it's absolutely breaking my heart.

I think it is a good thing you aren't pregnant (at least, I hope you aren't) by this male. He is being immature. I think I would be questioning his commitment to the relationship if he is so set on believing you cheated on him just because your vagina 'feels' different. This is starting to sound like someone who is searching for an escape clause and it is easier to make you the evil person than to accept his own change of emotions.

As we go through life our bodies go through changes. Many of them due to hormonal fluctuations. We aren't robots with parts that never change. If he wants things exactly the same every time then he can get a male masturbatory aid. However, even they change through usage and aging.

If you are concerned about the changes in your own body, talk to your doctor. If you are trying to conceive you should already have an ob/gyn you trust. If you don't then you need one.

I don't know. It just really bothers me that he's thinking this when I haven't done anything wrong. And I know pregnancy is not a factor now. So I can scratch that one off the list.