A.,
Please try not to worry about your husband leaving you. It will distress you and make things worse. Your past experience with men leaves that thought looming in the back of your mind. Men will sense the insecurity and try to flee from it - that may be why he is saying that you might need a little time away from each other. From your post, it sounds like he is devoted to you and your children (he's there for your daughters, and he calls to check up on them). It does sound like he may be a bit depressed or disillusioned by life (men can get that way sometimes, as can women). The flopping on the couch and watching TV is a sign that that could be going on and you can't afford to ignore that if you want your marriage to stay fresh and for you two to be closer.
I have been through periods like this with my husband and I finally figured out how to bring us closer, because hardly anything was more devastating to me than that "distant" feeling. Whenever I feel that distance between us, it becomes a signal that I need to make an extra effort to make him feel like #1. I can tell from your post that you are a great wife and mother, and you mention that you try to be the perfect wife. Trust me when I tell you that no man (unless he's an obsessive compulsive who needs some med) really wants a perfect wife. What he does want is a woman who is there for him, but even more than that, he wants a woman who makes him feel like he is in your thoughts and that HE IS A PRIORITY to you.
You spend time with your sister - maybe in his mind he thinks that she is a higher priority to you than he is. As important as your kids are, and they should be a priority, it sounds like it is time to let him know that he is #1. Then when you devote yourself to your children, other family members and friends he won't feel as threatened. Men sometimes have surprisingly fragile egos, and can be moody, just like us. It manifests itself differently sometimes in them, though.
I have found that the BEST way (for me anyway) to turn my husband around and remove that distance is to show him how special he is to me. You could try cooking a romantic meal for him after the kids have had their meal, at around 8:00. During this very special (not run of the mill meal - something he LOVES) it is time to open the line of communication. Ask him if he would like to talk about how you and he can have more fun. Just about every man LOVES to talk about the three letter word - SEX! Maybe he would like to talk about sharing sexual fantasies or discussing more creative ways that you two can be intimate. I was amazed when I discovered some of the thoughts and fantasies my husband had concerning us, but was too afraid to share with me for fear that I would label him a pervert. Unless his fantasy is a pedophile or violent one, there really is no fantasy that is off-limits, as long as you are discussing it, and not actually doing it. And if you are open to acting out some of the fantasies, as long as you are both in agreement and love and respect each other, you will grow closer and close that distance.
Maybe that won't be the case with you and your husband, but it worked for us, and I have since found from talking with others who have tried it that it is working for them. Men have all kinds of thoughts in their heads that they would like to share but are afraid to. Be careful if he does start opening up to you that you don't accidentally criticize his fantasies. If he does ask you to do something that you wouldn't consider (for example, having a threesome or going to a nudist resort), set your boundaries right away, but thank him for sharing his fantasy. Try to act out some of the fantasies at home with just the two of you. There is hardly anything men love better than for the woman they love to be creative sexually. It can take a lot of time and energy and be emotionally draining sometimes (for me anyway), but it really has paid off. When my husband tells me that he is so in love with me he can't stand it, and that other women couldn't hold a candle to me (even beautiful, perfectly shaped ones) I know I'm doing something right! And ever since we opened the line of sexual communication, with me setting firm boundaries on what is acceptable and what isn't, he is so much more respectful towards me. He comes to me first with important questions and concerns, instead of his friends and family. That is the biggest compliment he could pay to me and our marriage.
Sex is one of the few ways that men are able to readily express their love for us. I read once that it is hard for men to really open up their hearts and love us without the sex, and it is really hard for women to open up sexually without love. So help him along in the sex department (if you aren't doing so already) and see what happens - I would be greatly surprised if he doesn't start becoming more loving and closer to you.
And don't forget to pray, if you are a praying person. God will bless your marriage and remove any obstacles that might threaten it. Another interesting thing happened concerning my husband and church - as we became more open and communicative sexually, he actually started to enjoy going to church with me. He used to hate it and complain and do it only out of duty. I made a joke with him that we ended up taking seriously in a good way. I said, "How about I be the leader of our sex life and you be the leader spiritually?" He said, "Okay!" I asked if he was joking and he said no. Women have always been the one in charge sexually anyway. We are the ones to say no and set limits. By me being the one more in charge of setting the tone and taking more initiative, miraculously it has opened him up spiritually. I found him reading my Bible and reading some of the church publications soon after! He woke me up one Sunday so I wouldn't miss church! That is why I think praying over your marriage is important, as well.
And by the way, our marriage isn't perfect. We have been known to get into some nasty arguments, occasionally in front of the kids, which is a no-no, but we always make up in front of them too and hold ourselves accountable. No matter how great our marriage is, a month or two later, we will find ourselves in the doldrums - it happens so quickly because life gets so busy and sucks so much out of us. When he starts acting bored and distant, I know that is my call to action. When I do my part, he always will end up reciprocating in the end.
Sorry for going on so long - I just wanted to share what worked for us. I wish you much love and blessings in your marriage! Please keep us posted!