Sex life with long term partner

I hear quite often that people say their sex life or the spark has gone. I've been with my partner for 3 years now, got one baby together. I'm not sure if this is classed as long term or not but it's the longest relationship either of us have ever been in, and to me it seems long term. I feel we are still as attracted to each other as in the beginning. I have gained weight of course, but he still finds me attractive, I still find him attractive and when we get time to ourselves we just can't keep our hands off each other. Even if we're just cooking or sat together he does little things like slaps my bum or just generally has to touch me or kiss me. I don't feel our spark is going anywhere anytime soon, if anything we are much more attracted to each other now maybe because we know each other more and it's attraction in a variety of ways?