Is it normal to have sex only once a week?

For a woman it is normal. Personally I have a high sex drive, but the majority of women do not. Especially when she has two children and is probably really busy. Most of my male friends complain about this alot. When you get married don't expect it to change. In fact, it will probably even be less than once a week. You have to decide how important the sex part of the relationship is to you because its not going to change. I have the same problem with my bf. I can sympathize with how you feel.

It could just be that her sex drive isn't as high as yours, and once a week is normal for some people. In fact, quite common from what I have heard. However, it could also be that she is bored. Either way, if you are concerned about this, you need to talk to HER about it. It will be awkward, and probably really hard to bring up but it is worth it. You need to find out why she doesn't want sex as often as she used to. If she says she is bored, don't be offended because that doesn't help matters, instead come up with ways to spice it up.

Your relationship isn't new anymore, and at your age (and with kids in the picture) she's probably tired a lot and might not feel as sexy as when you two first got together and you were busy telling her how great she was. Think about her stress/tiredness level. Also, if you are just dropping into bed at the end of a rough day and assuming she's in the mood to have sex not sleep you, are so wrong. I think a lot of women need to feel "in the mood" so a little bit more effort on your behalf might go a long way. Start telling her when she looks attractive, does something impressive, or just simply that you love her, whatever. Don't take her for granted. Take the time to get away from the kids and have a "date night" every week, or find time for the two of you to do something you both enjoy together (it will put her back in the wanting to look sexy mode - and when she puts some effort into looking sexy she will feel sexy and then you will be in a much better position for getting her to have sex). Put some effort into the relationship and spend some time battering her up a little like you used to when you first got together - and no, not when you are already in the bedroom, try to be a little bit more sincere and believable. I know that many people think that longterm relationships are easier and require less effort, etc, but that is NOT really/entirely true. Stop putting in the effort and your relationship (and sex life) will go down the drain.

Other things: If you two are living together, how much free time do you each have? if she gets home from work, makes dinner, cleans up, cares for the kids, etc while you are sitting infront of the TV chilling out she probably physically just needs to sleep at the end of her day and is not in the same happy/relaxed mindset as you are. Split the household chores/child care duties so both of you have equivalent amounts of free time and your energy levels & sex drives might be more synchronized.
Also: did she put herself on the pill recently? One of the known side-effects (in many women) is eliminating their sex drive...
recently gained weight might also change how she feels about her body and consequently her desire to have sex.

Finally, if non of this helps and actually, even if it can, talking to her about her decreased sex-drive & what the two of you can do together to change it might be the best way of fixing your problems (just don't make it sound like something is wrong with her or like you are blaming her! - better to opt for approaches that suggest you miss the intimacy, or that focus on how attracted you are to her). Good luck! ;)

Personally, I've been with my boyfriend for about 4 months and we have sex usually 5 or 6 times each week. We spend every night together as well, but all relationships are different. I would just talk to her, because maybe you're not sending the signals her way either.

I think after dating a while having sex once a week is normal.

With those kids and being 35 and 40, once per week sounds pretty normal.

Talk with her, and see if the two of you can create more time and/or energy for each other.

Sounds like your children and family life have complicated things a bit. I wouldn't worry too much about it. You're still having sex! If you stopped completely, then there would be reason for concern. You might want to discuss it with her, and see if you can work it out.

Is she orgasming I mean the body changes a lot at that age I mean sheesh menopause?